摘要:

174 STOKES ON A CERTAIN REACTION OF QUININE. XI.-& a certaiib Reaction of Quinine. By Professor G. G. STOKES, F.R.S. (Read March 18th 1869.) INthe course of two papers on optical aubjects published in thq Philosophical Transactions I have mentioned a peculiar re- action of quinine having relation to its fluorescence." About that time I followed out the subject further and obtained result,s which were interesting to myself especially in relation to a classification of acids which they seemed to afford. Not being a chemist I did not venture to lay the results before the chemical world. I have however recently been encouraged by a chemical friend to think that a further statement of the resulte might prove of some interest to chemists. The reaction is best observed by diffused daylight entering a darkened room? through a hole in the shutter which may be * Phil.Trans. for 1852 p. 541 and for 1853,p. 394. .t-In default of a] darkened room a common box such aa an old pauking-ease may be readily altered so as to anawer very well. The box is wwn obliquely across ths cutting plane being parallel to one edge as indicated by the figure which denotes a vertical section. The aperture thus made is covered by a board nailed on containing a hole H destined to be covered by the glass plate which is kept from slipping down by a small ledge L. A por-tion of the upper covering of the box at E ia removed to allow the observer to see and mani- STOKES ON A CERTAIN REACTION OF QUININE. 175 four or five hchea gquare and which is covered with a deep violet glam,coloured by manganese.* In front of the hole is placed a white porcelain tablet or else one of the porcelain slabs with ehallow depressions used for colour tests.A solution of quinine in very weak alcohol is strong enough for the observa- tiona or ehe very minute fragments may be used. In some cases as for example with valerianic or benzoic acid the pre- sence of alcohol interferes with the reaction. It will conduce to brevity and clearness to describe in the first instance in a little detail the phenomena exhibited by two parkicular acids say sulphuric and hydrochloric. Let a series of drops of the quinine solution be deposited on the porcelain. If one of these be touched by a rod dipped in dilute sulphuric acid the beautiful fluorescence of the quinine iEi instantly developed.If another drop be similarly touched by a rod moistened with dilute hydrochloric acid no apparent eEect is pr0duced.t Nor is this all. If a little hydrochloric acid be introduced by a moistened rod into the fluorescing drop the fluorescence is immediately destroyed. If a little of the sulphuric acid be introduced into the drop containing only hydrochloric acid no effect is produced.$ If a series of drops of a solution of quinine in dilute sulphuric acid be deposited and a little solution of chloride of potassium sodium or ammonium be added the fluorescence is immediately pulate. Jn observing the box is placed near a window with its slant side turned towards the light ;the hole is covered with its glass ;the object is placed at 0;and the observer laoks in through E cavering his head with a dark cloth to exclude stray light.* Flint glasses answer best the colour given by manganese to crown glass being generally somewhat brownish. I have however seen one specimen of crown glass coloured by manganese the colour of which was as fine a purple as that of the tlint glasses. -t It is true that a solution of quinine in dilute hydrochloric acid is fluorescent and with concentrated sunlight or with sunlight uncondensed but analysed by absorption or dispersion the fluorescence comes out strongly. It is however notably inferior to that produced by sulphuric acid ;and for our immediate object a mode of observation in which it hardly if at all appears is even better than one adapted to bring out comparatively feeble degrees of fluorescence.When I speak in the text of 0uorescence being dest~oyed,the expression must be understood in this qualified sense. $ It must be understood that I am not here dealing with concentrated acids nor with any very great preponderance of one kind over another. I suppose all the solutions to be dilute and the quantity of acid employed of whatever kind to be many times that merely required to combine with the quinine. 176 STOKES ON A CERTAIN REACTION OF QUININE. destroyed. The action of sulphate of potassium &c. on a solution of quinine in water acidulated whether with hydro-chloric or sulphuric acid is in each case merely negative.t Now on trying a variety of acids I found that with hardly an exception unless when the acid character of the acid wag only indistinct the acids ranged themselverr with perfect definiteness into two classes which I will call class A and class B.Those of class A developed fluorescence in a solution of quinine in water just like sulphuric acid the amount of fluoresc- ence being comparable with that produced with sdphui<c acid and the tint the same. Those of class B not only did not produce it but destroyed it when produced by acids of the class A. Thisdestruction is produced by the alkaline saltR of the acids as well as by the fkee acids themselves and thus we are able to classify acids without having specimens of the free acids at hand.In the following lists those acids which were tried only in- directly by means of one or more of their alkaline salts -are distinguished by an asterisk :-Class A. Class B. Acetic Hydriodic' Arsenic Hydro bromic* Benzoic Hydrochloric Chloric Hydro ferroc yank* Citric Hydropalladioc yanic' Formic Hy dropla tinocyanic" Hyposulphuric* Hydrosnlphocyanic* Iodic Hyposulphurous* Malic Nitric Oxalic Perchloric Phosphoric Silico-fluoric Succinic Sulphuric Tartaric Valerianic f See the preceding note. STOKES ON A CERTAIN REACTION OF QUINIh%. 277 UnleRs a quinine solution be sufficiently dilute when alcohol is used iodic acid produces a precipitat.e. 111 what precedes it must be understmod that I refer in all cases to solutions.The character of the fluorescence of the salts of quinine in the solid statevaries from salt to salt. The solid iodate obtained by precipitation is strongly fluorescent with a blue considerably deeper than that of the solutions. It is not in all cases possible to try all the reactions stated to belong to the acids above mentioned. Thus in the case of iodic acid the solution cannot be tested by ferrocyanide of potassium which instantly decomposes the iodic acid. But the strong fluorescence of the iodic solution and the immediate destruction of the fluorescence by chloride of sodium &c. alone suffice to show definitely to which class iodic acid belongs. The absorption of the fluorogenic* rays by the yellow ferro- cyanide of potassium woiild itself alone account for the ap- parent destruction of the fluorescence ;f the salt were present in suficient quantity.Actually however the quantity which suffices to destroy the fluorescence is much less than what would be required to prevent its exhibition by the absorption either of the fluorogenic or of the fluorescent rays or of both. When the experiment is properly tried there cannot be a moment’s hesita- tionthat the removal of the fluorescence is a true chemical reaction and not a mere optical effect. Thia may be further proved by spreading a comparatively large quantity of the ferrocyanide solution in the form of a broad drop on glass and holding it immediately over the gleaming drop of the quinine solution when though the fluorogenic rays entering and the fluorescent rays leaving the drop have both to pass through the whole thickxess of the absorbing solution the fluorescence observed is only somewhat reduced.The absorption of the fluorescent rays in this case goes indeed for little ; it is the ab-sorption of the fluorogenic rays that we have to consider. That there is a real reaction and not a mere optical effect 1 have further proved by experiments in a pure spectrum which it would take too long to describe. By thia term I merely mean rays considered in their capacity of producing fluoreecence the introduction of such a term prevents circumlocution. It is con-venient also to have a name for the rays emitted by B fluorescent body.If these be called as they are a little further on $we.ucent no confusion can practically result though the term has of course a total1y different signification as applied to the rap or to the body emitting them. 178 STOKE3 ON A CERTAIN REACTION OF QUININE. Hyposulphurous acid is it is true rather easily decompoeed but the dwtruction of fluorescence by hyposulphite of soda ig quite independent of this circumatance. It takes place for instance at once on introducing tl very dilute solution of hypo-dphite of soda into a drop in which the fluorescence had been excited by very dilute citric or acetio acid. After these remarks which were necessary to prevent pwsible misconception we may return to our lists. A glance at these lists shows that the classification made by the quinine reaction ggrees almost exactly with the old distinction of ox-acih and hydracids.There is however one acid the hyposulphurow which in the quinine reaction ranges ihelf with perfect definite- ness in class B but which is not I believe usually ranked by chemists with the hydracids except in so far a8 acids in general have been regarded fiom this point of view. This led me to seek whether there might not be other analogies between hypo-sulphurous acid and the hydracids.' I have noticed the two following :-1 It ia kniown that a solution of ohloiida of mercury reddens litmus but the blue colour is restored by an alkaline chloride t4ough itaelf neutral to colour tests. Now the very same effect ia produced by hyposulphite of soda.This salt and chloride of mercury very readily decompose each other ; but if very dilute raolutioas be used the solution of chloride of mercury having been coloured by a little litmus it is easy to observe that the jrst effect of the introduction of the hyposulphite an effect which takes place immediately prior to the formation of any precipitate is to reetore the blue oolour. 2. It is known that cyanide of mercury is hardly decomposed by ox-acids so its simply to displace the hydrocyanic acid but readily by hydracids. Now ifa solution of hyposulphite of soda be added to one of cyanide of rnerqury the smell of hydrocyanic acid is immediately perceived. These circumstances bear out aa to hyrposulphurourr acid the dassificafion afforded by the quinine reaction.If them be a real difference of constitution between say sulphuric and hydro-chloric aci& expremed m epboh by writing the former (ac-mrhg to the old equivalents) SO3 . HO and not SO,. R,and in words by calling it an ox-acid the mere fact that the radical of hyposulphurom acid regarded as a hydracid contab oxygen does not of course oblige us to rward it a8 en ox-ad. It is STOKES ON A CERTAIN REACTION OF QUININE. 179 that difference of constitution whatever it may be which must decide and if we may trust the quinine reaction the ieolation of S,O, the analogue of chlorine would seem to be less improbable than that of S,O, the analogue of sulphuric anhydride. With hydrocyanic and hydrofluoric acih the reaction seemed doubtful.These acidra seemed to belong to clam B as regards the feeble amount of fluorescence which they developed but not to prevent the development of strong fluorescence by acetic sulphuric &c. acids. Ferridcyanide of potassium had certainly no such action as chloride of sodium or even ferrocyanide of potassium in destroying the fluorescence; but the deep c01ou.r of the salt prevented a satisfactory decision whether the acid really belonged to class A or resembled hydrocyanic acid in its action on quinine. The destruction of the fluorescence of a aolutiou of quinine in a dilute ox-acid on the introduction of a hydracid or ih salt would seem to indicate that the quinine combined by preference with the hydracid. It seemed to me that it would be intereHt- ing to restore if possible the fluorescence without precipitation by the introduction of a substance which should have a pre ferential af3init-y for the hydracid.In the case of hydrochloiia acid this may be effected by a salt such a8 the sulphate or nitrate of the red oxide of mercury. In trying the experiment it ia convenient to use only a little hydrochloric acid or chloride of sodium &c. otherwise the sparingly soluble chloride of mercury and quinine is precipitated which however redissolves on theaddition of more of the mercuric salt. That the restorai tion of fluorescence is not a mere effect of the acid introduced with the mercuric salt may be proved by varying the experi- ment. Let quinine be dissolved with more nitric or sulphwio acid than would otherwise have been necessary; add a little hydrochlaric acid 80 as barely to destroy the fluare8cence and then introduce a little precipitate of oxide of rneroury stirring it As the oxide dissolvels the fluorescence returns.up. Chloride of mercury does not impair the fluorescence of q solution of quinine in an ox-acid ;if anything it sometbeg SWMB slightly to increase it. Chloride of barium strontium calcium magaesium manganese or aim acts like doride a€ ljodium. The fluoi-escence destroyed by a chloride is in Borne measure iwtored by nitrate of cadmium. Whes the fluorescence ip1 destroyed by bromide or iodide of 180 STOKES ON A CERTBIN R'EACTION OF QUININE. potassium,it may be restored by oxide of mercury just as in the case ofan alkaline chloride and under the same conditions.The precipitate of chloiide of mercury and quinine which is liable to be produced in trying the above reactions is strongly fluorescent with a blue which lseems to be a trifle greener than that of the solutions. The corresponding precipitate which may be obtained with bromide of potasaium doubtless a bromide of mercury and quinine is white and shows a pretty strong orange fluorescence a very unusual colour for the fluorescence of a white substance. The iodide is pale yellow and not sensibly ffuorescent at leaat examined by daylight with coloured glasses. At the conclusiofi of this paper Dr. Odling made the follow- ing observations respecting the conatitution of hyposulphurous acid :-Sodium hyposulphite is usually represented by the formula Na,S,O, together with a molecule of water; and this mole-cule of water is emential not only to the hyposulphite of sodium but likewise to all the hyposulphites such as the hyposulphite of barium the double hyposulphite of silver and sodium and the double hyposulphite of gold and sodium.Ic now instead of writing the formula of the sodium mlt as above we put it all together in the fcwm Nn,H,S,O, we have a formula which admits of being halved and may accordingly be supposed to represent a double molecule of the sodium salt. If this be the case the single molecule will be NaHSO cor-responding to an acid H,SO,. Regarded in this manner hyposulphurone acid forms the first term of a serieB whose two folowing terms are sulphurous acid H,SO, and sulphuric acid H,SO, with this difference howerer that in the two latter acids both the atoms of hydrogen are replaceable by metals whereas in hyposulphurous acid only one hydrogen atom is thus replaceable just as in formic acid H2C02,which as pointed out a few yeare ago by Dr.A. Duprh may be regarded a8 the carbon analogue of hyposulphurous acid. But though hyposulphurous and formic acids may be analo- gous so far as their empirical composition is concerned it by no means follows that they are analogous so far as regards their internal molecular arrangement. Formic acid is well recog- STOKES ON A CERTAIN REACTION OF QlJINME. 181 nized by its properties to be an oxacid that is to say an acid in which the basic hydrogen is directly combined with oxygen.With regard to hyposulphurous acid our knowledge is far less complete; but it is quite conceivable that this acid may be a hydracid that is to say an acid in which the basic hydrogen is connected with oxygen (if present) not directly but only through the medium of other elements. The difference of constitution between these two classes of acids may be illusltrated by the following examples :- H ydracida. Oxacids. Hydrochloric HC1. HOC1 hypochiorous. Hydrocyanic HCN. HOCN cyanic. Nitrous HNO,. HON02 nitiic. Nitrous acid cannot indeed be placed with certainty among the hydracids but considering the great number of cases in which NO2 is capable of taking the place of chlorine or of cyanogen it is by no means improbable that nitrous acid may be analogous in constitution to hydrochloric and hydrocyanic acids.The three acids of sulphur above mentioned may be formu- lated thus :- H7 HJSO Hyposulphurous. Sulphurous. Sulphuric. sulphuric acid being an oxacid hyposulphurous acid a hydracid and sulphurous acid an intermediate acid or hydroxacid. With regard to the analogy of fact between the hyposulphites and the halogen salts the hyposdphites certainly correspond with the latter in their remarkable tendency to form double salts the constitution of which is not satisfactorily accounted for- analogous for example to the chlorides of mercury and sodium or of mercury and ammonium. These are double salts the constitution of which cannot be accounted for according to the commonly received notions of atomicity unless indeed we follow Mr. Wanklyn in assigning to the alkali-metals a higher atomicity than is generally accorded to them.

ISSN:0368-1769    

DOI:10.1039/JS8692200174

出版商:RSC    

年代:1869

数据来源: RSC

摘要:

182 XIL-On the Determination of the cc Total Carbon” in Cast-Iron. By ARTHURH. ELLIOTT. (Read March 18th 1869.) SOME time ago having occasion to determine the “total carbon” in some cast iron I had much difficulty in finding a thoroughly convenient process. The following method principally adapted from Ullgren (Ann. Ch. Pharm. cxxiv. 59) gives satisfactory results and is easily worked. Preparation of the Specimen.-Bore the iron with a drill; powder the boiings in a porcelain mortar picking out any large pieces and rejecting them. Separation of the Carbon f~omt?te Iron.-Take a weighed quantity (fi-om 2 to 2.5 grms.) of the powdered iron; treat it with 50 C.C. of a solution of sulphate of copper containing one part of the pure crystallised salt in 5 parts of water; and heat very gently for about 10 minutes.The iron will dissolve and metallic copper separate the carbon remaining undissolved. The reason why sulphate of copper is used in preference to chloride of copper is that it does not contain fkee acid which if present would cause an evolution of hydrocarbons and coil- sequently a loss of carbon.* Now add 20 C.C. of a solution of chloride of copper containing 1 part of the salt in 2 parts of water and 50 C.C. of strong hydrochloric acid and heat the mixture at a temperature near the boiling point for some time until the separated copper has dissolved. Collect the carbon on a filter made of a piece of rather wide combustion-tube about 15centimetres long one endof which is drawn out to a point 4millimetres wide and stopped first with broken glass (angular pieces about the size of small peas answer best) and then loosely with ignited asbestos.To see whether any carbon passes at firat mix the deeply-coloured solution with strong hydrochloric acid (to prevent the separation of basic chloride of copper) and then dilute with water ;by this means any carbon that may have passed will be rendered visible ; if the solution contains carbon it should be boiled and passed * The smell obtained when heating with sulphate of copper is due to a mall quantity of phosphoretted hydrogen. A. H. ELLIOTT ON THE DETERMINATION ETC. 183 through the filter again. Finally wash the carbon with boiling water till fiee from chlorides. Conversion of the Carbon into Carbonic Acid and Determination ofthe latter.-Cut the tube containing the carbon at about 2 or 3 centim.above the latter and transfer the contents to the flask by blowing carefully into the pointed end. Wash any particles that may remain in the tube into the flask with a very fine jet of water so as to uae as little water as possible ;* now add about 3 grm. of chromic acid and attach the flask to the rest of the apparatus. The apparatus is represented in the annexed woodcut. a is a tube containing soda-lime attachable to the funnel tube b bya cork. b isprovided with a glass tap. The flask c should hold about 200 c.c. and the bottle d about 60 c.c.; the latter is one-third filled with strong 6ulph~n-i~ acid. The U-tube e which is about TOTALCARBONIN CAST-IRON.ii t 'I e 30centimetres high and about 2 cmtimetres in internal diameter is filledwith pumicet saturatedwith sulphuric acid. The sulphuric acid added to saturate the pumice should not stop the passage at the bottom of the U-tube as this unneceraaariliy incrasw the * If mote than 15 C.C. of water is used in waahing prsportionately moresulgi~~ie wid must he added to the flask when heating. 9 Previously freed from hydrochloric and hgdrofluoric acids by heating with sulphuric acid washing and drying. 184 A. H. ELLIOTT ON THE DETERMINATION ETC. pressure to be overcome by the evolved gas. The remaining tubes are for absorbing the carbonic acid fis 15 centimetres high and 1.5 centim. in internal dia.meter it is filled with good soda-lime ; 9 is 9 centimetres high and 8 millimetres in internal diameter this is filled with pumice* saturated with sulphuric acid.Sulphuric acid is used iu preference to chloride of calcium because the latter substance does not seemcompetent to stop all moisture fiom pass- ing it. The flexible joints must be bound with copper wire. All being ready add to the contents of the flask about 30 C.C. of strong sulphuric acid through a small funnel placed in the neck of the funnel t.ube b a small quantity at fist; then shake the flask so as to mix the contents completely and add the rest. Shake again close the tap of the funnel-tube and heat the flask gently till it boils. While heating the flask the gas should not be allowed to pass theLott.led faster thanthree bubblee in a second.When the contents of the flask boil keep boiliiig for about a minute then open the tap of the funnel-tube remove the heat and attach the soda-lime tube a. Having done this attach an aspirator to the U-tube g and draw air through the apparatus at the rate of two or three bubbles per second. The sulphuric acid inthebottle d will lastfor three andthesoda- lime in f can only be trusted for two analyses ; the large U-tube and the other soda-lime tube will last for about aix analyses. Test AnaZyses.-5 analyseR of one specimen of iron gave respec- tively-3.40 3.40 3.38 3.39 and 3-40 per cent. of carbon. School of Chemistry Qreat Marlborough Street. The President remarked that in prepai-ing the specimen of iron for analysis a selection had been taken fiom the borings.Now all iron is of so complex a character that in rejecting any part of a given sample there is a danger of rejecting a portion of the iron having a different proportion of the metal to the carbon as compared with the rest. This however has nothing to do with the method of analysis adopted when the specimen has been well se1ected.f * Previously freed from hydrochloric and hydrofluoric acids by heating with sulphuric acid washing and drying. t The large pieces proposed to be rejected are those pieces which are pushed out by the point of the drill when it has nearly passed through the iron. This can be entirely obviated by not allowing the drill to bore the iron too thin.-A. H. ELLIOTT.

ISSN:0368-1769    

DOI:10.1039/JS8692200182

出版商:RSC    

年代:1869

数据来源: RSC

摘要:

185 XIK-On some Decompositiom of the Acids of the Acetic Series. By ERNESTT. CHAPMANand MILXS H. SMITH. [Read April lst 1869.) Fi?*st.-Action of Bromine on Acetate of Lead.-This is not properly a decomposition of acetic acid. When bromine is added to acetate of lead in aqueous solution a brown pre- cipitate is at once formed. Without the aid of external heat the action stops after the addition of a very small quantity of bromine. On warning however the formation of the brown precipitate proceeds until oue equivalent of bromine has been added to two of acetate of lead. When this point has been reached no more precipitate is formed and no further action of any kind takes place on the addition of more bromine. No gas whatever is evolved in this reaction.The brown solid is per- oxide of lead and the liquid contains bromide of lead and acetic acid. The decomposition possibly consists in the with- drawal of lead from one atom of acetate of lead by bromine whereby peroxide of acetyl would be formed and would at once oxidise another portion of the lead to peroxide; or the bromine may simply act in the presence of water a8 an oxidising agent producing peroxide of hydrogen and hydro- bromic acid when of course we should get acetic acid by the action of the hydrobromic acid on acetate of lead ;the peroxide of hydrogen would oxidise the other molecule of acetate of lead giving us peroxide of lead and acetic acid. No matter which way the decomposition really goes it may be represented as follows :-2C,H,Pb02 + H20 + Br = 2C$I,O + PbO + PbBr.This equation is established by weighing the quantities of acetate and bromine employed; by weighing the peroxide of lead as sulphate of lead; and by distilling off the acetic acid converting it into acetate of silver and determining the silver. We think it unnecessary to subjoin the details of these operations. VOL. XXII. P 186 CHAPMAN AND SMITH OM SOME DECOMPOSITIONS Second.-Action of Brombie on Acetate of Potash,-Two ecpi-dents of bromine and one of acetate of pota#sh together with water were sealed up in a strong digestion-tube and heated for many hours in the water-bath. Bromine is tolerably soluble in concentrated solution of acetate of potash. After the tube ha8d been heated for five hours it was opened when abundance of gas escaped-the gas proved to be carbonic acid.It was again sealed up and again heated for about six hours. On cooling and opening the tube more gas escaped- still carbonic acid. The contents of the tube were still much coloured by the bromine. The action had now very nearly if not quite terminated. To remove the excess of bromine a por-tion of the contents of the tube was treated with a dilute solution of sulphite of soda. This of course produced some little warmth and an inflammable gas having an ethereal odour escaped from the liquid. Freed from carbonic acid by treat- ment with dilute caustic potash this gas was found to bum with a green-edged flame producing much hydrobromic acid. We have no doubt that it was bromide of methyl and owed its origin to the following change- C,H,KO + 2Br = KBr + CO + CH,Br.At the same time traces of liquid were observed heavy and insoluble in water ; probably brominated bromide. The saline product of the reaction is bromide of potassium. Acetic acid i8 set free and it is impossible to push the action very far. No bromnte of potassizrrn is formed as it must have been had the reaction taken a different course to that described above. By the bromination of the bromide of methyl hydrobromic acid would be set free which would of coume liberate acetic acid. Direct experiment has shown that a mixture of acetate of' potash hydrobromic acid and free bromine liberates no car-bonic acid whatsoever. The reason why we cannot push the action further is therefore evident viz.that the acid produced brings it to a stand-still. By distilling out the bromine neutralking and adding bromine afresh we can carry the action hther until we are again stopped by the prmence of acid. Simply adding alkali to the mixture strongly coloured with bromine has the same effect but if we take a solution of potash and add bromine to it so long as it is deoolorised thia solution is incapable of acting on the acetate. 187 OF THE ACIDS OF TRE ACETIC SERIES. Bromine acts upon solution of acetate of potash with great rapidity in direct sun-light; but the action comes to a close precisely as in the former case ; the products also are the same. Third.-Action of Chlorine on Acetate of Potash in Aqueous Solution.-The action is strictly analogous to that of bromine and like the latter rapidly comes to a close.It can be re- started by the addition of alkali. Bi-chloiide of methylene is amongst the products of this reaction; probably under appro- piiate circumstances it would furnish a convenient source of this substance. The action of chlorine is much brisker than that of bromine. Fourth.-Action of Bromine on Valerianate of Soda in Aqueous Solution.-This reaction takes place more readily than that with the acetate of potash; and the products of the reaction are more easily collected and examined. Aqueous solution of vale-iianate of soda is perfectly miscible with bromine. The mixture reacts slowly at ordinary temperatures rather quickly in the water-bath and with great rapidity in direct sun-light the pro- ducts being carbonic acid and bromide of butyl more or less brominated.This reaction like the foregoing speedily reaches its limit but can be re-started by the addition of potash. By fkact.iona1 distillation of the liquid products we obtained a body having about the boiling point of bibromide of butylene. We could not succeed in getting it perfectly pure but it contained approximately the percentage of bromine required by bibromide of butylene. This mbstance constitutes about a third of the liquid products of the reaction. There is apparently a very small quantity of bromide of butyl and a very large quantity of highly brominated substance produced at the same time.Iodine has exceedingly little action on the alkaline salts of the fatty acids. On acetate of lead a reaction is obtained apparently analogous to the action of bromine on the aame acetate. The action of iodine on valeiianate of silver has yet to be investigated. At present we only know that there is an action and that the liquid products are of not very high boiling point. We have postponed the investigation of thils reaction until we are in possession of valeiianic acid which- does not consist of a mixture of isomeric acids. We have res~l0nto believe that the action of iodine on valerianate of 188 CHAPMAN AND SMITH ON SOME DECOMPOSITIONS silver differs with the different isomers. This reaction dl we trust enable us to descend from a fatty acid to the alcohol immediately below it i.e.one containing one atom less carbon. On the Action of Nitric Ethers on Acetic Acid.-A short time since Dittmar published a paper on the tension of the vapours of acetate of methyl and formiate of ethyl. In this paper he mentioned that oxalate of methyl though hardly attacked by glacial acetic acid is rapidly converted into acetate of methyl if a little hydrochloric acid be added to the mixture. Similarly glacial acetic acid is almost without action on nitrate of amyl. We believe thereis no actionwhatsoever ;the additioii of a few drops of sulphuric acid however causes a somewhat violent reaction t'o take place. Apparently the same sulphuric acid can cause this reaction with an indefinite quantity of the mixed acid and nitrate.Fifth.-Nitrate of Amyl and Acetic A did in presence of XU+hiiric Acid.-Nitrate of amyl was added drop by drop to a warm mix-ture of 20 parts of glacial acetic acid and 1 part of concentrated sulphurk acid. No external heat is requisite after the first few moments. A regular evolution of' gas is set up and very considerable heat evolved. The evolved gases were passed through an inverted L iebig's condenser and then collected for examination. They consisted of carbonic a.cid a little nitrogen a trace of binoxide of nitrogen and an inflammable gas. This latter is soluble to a great extent in water i.e. water takes up four or five times its volume. It is completely and readily soluble in .solution of protochloride of iron to which it commu-nicates a dark colour.On boiling this solution pure nitric oxide is obtained together with methylic a.ZcohoZ. The methylic alcohol was recognised by converting it into iodide of methyl. An attempt was rna.de to obtain the iodide by passing the gases evolved directly into concentrated hydriodic acid but without success. On sealing up some of the gas with a little hydriodic acid and warming it slightly for an hour or so abundance of free iodine made its appearance. The liquid products of the reaction are acetate of amyl together with traces of acetate of methyl; the inflammable gas iR nitrite of methyl. It is very difficult to give direct proof of this assertion. That it consists of methyl together with an oxide of nitrogen is clear ;but that OF THX ACIDS OF THE ACETIC SERIES 189 it is nitrite of methyl must rest on the fact that wTe know no other gaseous compound containing methyl and oxide of nitrogen together with the facts that its very peculiar smell taste and method of burning are identical with those of that body.We regard these as sufficient evidence; actual proof could of course be obtained by absorbing the gas in a solution of proto-salt of iron of known strength distilling out, measuring the nitric oxide so liberated and then titrating the iron. This course of proceeding would be exceedingly troublesome and appears to UEI superfluous. The reaction may be represented as follows leaving out of consideration the amyl and the sul- phuric acid i.e.regarding the reaction as occurring between nitric acid and acetic acid- HNO + C,H,O = CO + CH,NO + H,O. Taking the amyl into consideration the reaction may be repre- sented thus- The acetate of inethyl doubtless owes its origin to a aecondary reaction between tthe nascent nitiite of methyl and the excess of glacial acetic acid. Sixth.-ATitrate of Butyl and Glacial -4cetic Acid in presence qf Sulphulic Acid.-The action is precisely similar to the one above described butyl being substituted for amyl. Senenth.-Nitrate of Ethyl and Glacial Acetic Acid inpresence of Sulplturic Acid.-Very similar to the reaction above described differing only from it in this that the nitrate of ethyl appears to decompose to some extent simply by the heat of the reaction and that we get some of the products of its decomposition along with the others.By reducing the quantity of sulphuric acid adding the nitrate very slowly and making the reaction proceed as alowly as it will the result is exactly the same as when the nitrates of amyl or butyl are employed. Eightli.-Nitrate of Methyl and GlacialAcetic Acid in presence OJ Sztlrphuric Acid.-The action here is quite different. We believe; it is the methyl of the nitrate of methyl which is oxidised and 190 CHAPMAN AM SXITE ON SOME DECOMPOSITIONS &c. not the acetic acid. Much red he is produced in thia reaction ; we believe it may be expremed aa follows :-aCH,NO = 2CH,NO + HNO + CO + B,O. Very probably a reaction analogous to that with the higher nitrates takes place at the same time.It is however almost impossible to prove whether the acetic acid does or does not take any part in this reaction. Ninth.-Nitric Ethers andvaleriank Acid inpresetzc8 of Sul-phuric Acid.-We have made experiments on the action of the various nitrates on valerianic acid. We believe the reaction to be exactly analogous to those with acetic acid but the excess of valerianic acid at once decomposes the resultant nitrate of butyl; as in the case of the action of iodine on valerianate of silver we believe that differences will be observed between the different valerianic acids and postpone a detailed investiga- tion until we know more of the nature differenccs and modes of separafion of the valeiianic acids which are ordinarily found mixed together.dl attempts to aubgtitute nitric acid or a metallic nitrate for nitric ethers in the above reaction proved unavailing. Tenth.-Action of Fmic Acid on Nitrats of Amy1 in presence of &$.phuric Acid.-These bodies act on each other in the presence of sulphuiic acid giving riae to fbdate of amyl protoxide of nitrogen carbonic acid and water. Some red fume is at the atme time produced. Mr. Perkin mentioned aome expeiiments* made by Mr. Dnppa on the action of chlorine on the acetates and salts of ather acids in which the chloridels of the corresponding alcohol- radicals had been obtained. Acetates thus treated yielded chloride of methyl and succinates yielded chloride of ethylene. He himself had found that thechloride of methyl thus obtained yielded the ordinary crystalline hydrate when treated with ice- mld water behaving ill fact just like the chloride of methyl oM&,ed from methylic alcohol and hydrochloric acid.Th.e President (Dr. William ~3 on) inquired whether the chlo- PERKIN ON COUMARIC ACID. ride of methylene resulting from the action of chlorine upon potassic acetate was produced in presence of water? Mr. Chapman replied that it was. When chlorine is passed somewhat rapidly into a solution of acetate of potash kept warm and neutralized from time to time with potash a veiy notable quantity of chloride of methylene is formed; but it is very volatile and must therefore be condensed with great care as otherwise it will be caiied away with the carbonic acid.

ISSN:0368-1769    

DOI:10.1039/JS8692200185

出版商:RSC    

年代:1869

数据来源: RSC

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PERKIN ON COUMARIC ACID. XIV.-Note on Coutmn'c Acid By W. H. PERKIN, F.R.S. [Read April lst 1869.1 FITTIG,in a paper published in the Chemical News on the constitution of coumarin and coumaric acid after criticizing my theoretical conclusions or rather speculations asmmeB that coumarin is not formed from the hydride of aceto-salicyl a8 1 have stated but that it results from the previous formation of coumaric acid. It will be remembered that Bertagnini Borne-time since stated that the hydlide of benaoyl when treated with chloride of acetyl yields cinnamic acid and Fittig very naturally supposed that because I had worked with the hydride of salicyl aod acetic anhydride (acetate of acetyl) I bad ob-tained a similar reaction and formed coumaric acid which would then be viewed as oxycinnamic acid thus- C,H,O + C2H,0C1 = C,H,O + Ha Hydride of Chloride of Cinnamic beazoyl Wtyl.acid. C,EI,O -I-C,H,O,C,B,O = C9H,0 + HC,H,O,; Bgdride of Acefate Q€ Coumrrric or ACetie salicyl. acetyl. ox ycinnamic acid. acid. and the coumaric acid being formed in presence of acetic anhydride and subjected to a high temperature loses a mole- cule of water and gives coumarin. He therefore assumes that 192 PERKIN ON COUMdRfC ACfD. coumarin is the anhydride of coumaric acid standing to it in the same relation as lactide to lactic acid C,H,O -H20 = C3H,02 Lactic acid. Lactide. CgH,03 -H20 = C9H602 Coiimaric acid. Coumarin. But the point is this,-has coumarin the properties of an anhydride at all t First of all it is formed in the plant in presence of water ; therefore one would scarcely expect it to be an anhydride.Again you may crystallise it as many times as you like from water and it is not changed. Moreover you may boil it in strong potash and you get a sarine compound of coumarin; but the moment you add an acid the coumarin separates unchanged. This is not a simple solution of coumarin in potash. It is a chemical compound of coumarin with the alkali the nature of which I cannot quite understand. Again on adding nitrate of silver to a solution of potash which has been perfectly saturated with coumaik we obtain a beautiful yellow precipitate; arid this compound on analysis gives the formula of coumarin plus oxide of silver ;that is CgH,O .Ag,O analo-gous to the silver compound obtained by B 1 ei bt re u fjrornnitro-coumaiin.That it is it compound of coumarin is easily seen by decomposing it with nitric acid which removes the oxide of silver and yields pure coumarin. Artificial coumarin and all its homolopes likewise form compounds with caustic potash and in the case of either of the homologues as the potash con- centrates on boiling the new compound separates on the top as an oily layer which on cooling becomes a sticky mass. Again, if coumarin were an anhydride it should yield an amide with ammonia ;but it does not do so. Therefore I think that what- ever the constitution of coumarin may be it is very evident it is not an anhydride as Fittig supposed ittto be. In fact it is not an easy matter to produce coumaric acid from coumarin a boiling supersaturated solution of caustic alkali being required.

ISSN:0368-1769    

DOI:10.1039/JS8692200191

出版商:RSC    

年代:1869

数据来源: RSC

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193 XV.-On the Propyl Compounds derived from the Propjiic Alcohol of Fermen tation. By ERNEST H. SMITH. T. CHAPMANand MILES (R.ead April 15th 1869.) INa paper read before this Society 18th March 1859 we make mention of a large quantity of liquid which no amount of fi-ac-tional distillation appeared capable of splitting into definite bodies. It boiled through a range of 27' viz. from 79' to 106O. One great difficulty in its fractional distillation is that it is nearly impossible to render it perfectly dry. It was digested with a large excess of hydrobromic acid precisely in the manner described by us when speaking of bromide of butyl in the paper above referred to. By this means it was converted into bromides. These bromides were carefully fractionally distilled and split up into three fractions the first very small in amount boiling below 70° the next boiling between 70' and 71° and the third boiling up to 92'.This latter fraction consisted for the most part of bromide of butyl and about seven-eighths of it were obtained as pure bromide of butyl. The liquid boiling between 70' and 71' was repeatedly subjected to fractional dis-tillation whereby traces of liquid boiling at higher and lower boiling points were removed. The liquid now remaining weighed 284 grammes and was as will be proved elsewhere bromide of propyl. It is a colourless liquid of peculiar and rather dig-agreeable smell much more closely resembling bromide of ethyl than bromide of butyl. Its boiling point is between 70'9 and 70O.8 under a pressure of 762 mm.bar. Its specific gravity at 16' is 1.3532. Treated with alcoholic- potash it is readily decomposed without evolution of the dightest trace of olefiiie. With acetate of potash and glacial acetic acid it is slowly decomposed in the water-bath yielding acetate of propyl and bromide of potassium not the slightest trace of gas being evolved. It is almost impossible to complete the decomposition though more than 90 per cent. of bromide appears to be decom- posed. It is not readily decomposed by acetate of silver unless ~70~. XXII. Q the latter be only barely moistened with acetic acid nor is it easier to complete the decomposition with this reagent than with the acetate of potash. With dilute sodium amalgam and acetic ether it is readily and apparently completely converted into mercury-propyl.With cyanide of potassium and alcohol cyanide of ppy1 irJ readily obtained. With cyanide of mercury decomposition is slow and the resulting cyanide is immediately deodorised on treatment with an acid. It is in fact iso-cyanide. Sodium has comparatively little action on the bromide but attacks it rapidly when ether is added and almost explosively if sealed up and heated with the pure bromide in the water-bath. The bromide may be agitated with concentrated sulphuric acid without undergoing any change. If it be heated however decomposition takes place. Propylic alcohol may be obtained from bromide of propyl by converting this compound into the acetate and then de composing the acetate with potash.As it is exceedingly difEcult to complete the conversion of the bromide into the acetate we took the impure acetate containing the trace of bromide aealed it up with strong aqueous ammonia and di-gested it in the water-bath; whereby the bromide was con-verted into bromide of propylamine and the acetate though only very partially into the alcohol. The contents of the sealed tube were neutralised with acetic acid and dist-illed the distil- late saturated with carbonate of potash and the oily layer decanted. This oily layer consists of mixed alcohol and acetate. It is treated with powdered caustic soda which rapidly and completely converts it into the alcohol. The alcohol is dried over carbonate of potash and then over caustic baryta.Propylic alcohol is a colourless tolerably mobile liquid of a singularly intense though not disagreeable odour reminding one of common alcohol and not in the slightest degree resembling amylic alcohol. It is soluble in water i-n all proportions and is by far the 'most difficult substance to dry with which we are acquainted. It boils at between 97' and 98' under a pressure of 770 mm. bar. Its specific gravity at 16' C. ie *8120. On oxidation it yields propionic acid unaccompanied by carbonic acid. Treated with strong hydriodic acid it ~EI con-verted into iodide of propyl. DERIVED FROM PROPYLIC ALCOHOL OF FERLIIEhTATION. 195 Iodide of propyl is a colowless mobile liquid resembling iodide of ethyl in smell; it boils at between 102' and 103' under a pressure of 770 mm.bar. Its specific gravity at 16O is 1.7343. It is much more easily decomposed by acetate of potash and glacial acetic acid than the bromide and would doubtless form a far better source of the alcohol. Acetate of propyl was not obtained free from the alcohol; it appears to be a liquid of much greater density than the gene- rality of the acetates. Its odour somewhat resembles that of acetate of butyl but is fresher. Propyl compounds appear at the present moment to be in the hands of several chemists who have already published memoirs upon them We have not therefore thought it necessary to make a very detailed examination of them and publish the above more as a confirmation of the work already done on this subject than with any other view.Fittig has recently pub- lished an account of bromide of propyl having singularly enough adopted the conversion of the mixed alcohols into the bromides as a step in the process of separation we indepen- dently having done precisely the same. It will be observed that we give the boiling-point of bromide of propyl a trifle lower than Fittig. Judging from his analytical numbers his bromide must have contained a trace of some higher homologue which would tend to account for the difference of a degree between us. We subjoin a table showing the differences in physical pro- perties of the normal propyl compounds described above and the iso-propyl compounds. Boiling Point. Speeific Gravity.Name of Compound. Primary Secondary. Primary. Secondary. I ~~ # Alcohol .............. -812 -791 at 15C. "*5 60O-63" 1-3532 1.320 at 13C. Bromide .............. 70"" 84" Iodide ................ 102" 90" 1.7343 1.70 at 15C. The chemical differences between the primary and secondary alcohols are quite as striking as the physical ones. Iodide of * The specific gravities of the primary compounds are all taken at 16"C. Q2 196 CHAPMAN AND SMITH ON THE PROPYL COMPOUNDS normal propyl and ethylate of soda give rise to ethyl-propyl- ether and no propylene. The iso-iodide is almost wholly converted into propylene ; the normal alcohol yields propionic acid on oxidation ; the iso-alcohol acetic and carbonic acids. NOTE.-In our fractionation of fusel-oil we obtained two or three litres of a liquid which consisted for the most part of ethylic alcohol but contained traces of a higher alcohol.This liquid boiled at between 78O and 80° and it appeared a hopeless task to separate out the higher alcohols by fractional distilla- tion. Since the above work on the propyl-compounds was completed we have devised a method by which this separation can be effected. The alcohol is mixed with twice iCs volume of hydriodic acid of sp. gr. 1-7 and the mixture distilled. The distillate consists of an alcoholic iodide alcohol and water. The whole of the higher a.lcohols are converted into iodides and are found in the first portion of iodide which distils over. The latter portion consists of pure iodide of ethyl.The iodides may of course readily be separated by fractional distillation. APPENDIX. Evidence on which the above account of the primary propyl compounds rests. A. Combustion of bromide propyl. I. Burnt with chromate of leadjand copper turnings -9214 grm. of the bromide yielded *986lCO and *4768 H,O. IT. Digested with nitric acid and nitrate of silver *3838 yielded -5872 of bromide of silver. From these data the following percentages are calculated :-Theory. Found. c ........ 36 29-27 29.19 H ........ 7 5-69 5.75 Br,. ...... 80 65.04 65.11 ---_-123 100*00 100.05 The equivalent deduced fi-om the determination of bromine in this analysis is 42-87 instead of 43. B. Proof that we are dealing with normal propyl.The alcohol oxidised with 10 per cent. chromic solution DERIVED FROM PROPYLIC ALCOHOL OF FERMENTATION. 197 yielded an acid which converted into a baryta-salt gave the following numbers :-Salt taken 0.2985 yielded 0-2475 sulphate of baryta. Therefore 48*75 per cent. of barium. Propionate requires 48.41. C. Purity of the alcohol and of the iodide were reciprocally determined by the yield of iodide fiom the alcohol. The operation was conducted on a small scale and could only pretend to approximate accuracy. 8.00 of the alcohol were sealed up in a digestion tube with great excess of hydriodic acid and the tube heated in the water-bath for a few minutes. It was cooled and opened its contents transferred to a small distilling vessel water added and the whole carefully distilled.When the iodide ceased to come over the condenser was allowed to get hot whereby all the small drops of iodide adhering to it were driven out into the receiver. The iodide in the receiver was shaken with a little cold water which caused it to eollect in one large drop. It was carefully removed with a pipette transferred to a tarred flask and weighed. It weighed 22.8 grms. The iodide was of course wet though no drops of water could be seen adher- ingto it. Assuming it to contain 1 per cent. of water certainly more than it did contain we obtained 22-57 as the yield of iodide. 100 parts of propylic alcohol should yield 283.3 of iodide. Assuming our allowance for moisture to be correct we obtained 282.13. Making no allowance for moisture we obtained 285.00. Of course as the moisture waa not actually determined here and indeed hardly could be on so sinall a portion this number only shows that the alcohol was very nearly pure. We adopt 1 per cent of moisture simply because in various other iodides in which we have actually determined the amount of moisture it varies between 05 and 08pi-cent. 1 per cent. is therefore certainly sufficient to cover the moisture.

ISSN:0368-1769    

DOI:10.1039/JS8692200193

出版商:RSC    

年代:1869

数据来源: RSC

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198 XQI.-A’ote on Bromide of Amyl. By ERNESTT.CHAPMAN,and MILES H. SMITH. (Read April Xth 1869.) THEproperties of this substance are generally inaccurately given or not given at all. Thus in “Watts’s Dictionary” neither boiling-point nor specific gravity is given. In the last edition of “Miller’s Elements of Chemistry” both are given incorrectly. Bromide of amyl is a colourless mobile liquid of peculiar and not unpleasant odour. It boils at 121” C. at the normal pressure; its specific gravity ia 1.217 at 16” C. It rotates a ray of polarized light to the right when prepared from a rotating sample of amylic alcohol. The bromides both of rotating and non-rotating amyl appear to have the same boiling-point ; at any rate after repeated distillations the first and last portions still rotated absolutely alike.The bromide at its boiling-point is very energetically attacked by sodium. The bromide above described is prepared by saturating amFlic alcohol with hydrobromic acid gas mixing this solu- tion with its own volume of aqueous hydrobrornic acid and digesting the mixture in a closed vessel in the water-bath for an hour or so. It may be made without the use of pressure- vessels by heating the mixture in a flask to which an inverted condenser is attached. The heat must however be very gradually applied in this case and a certain amount of hydro- bromic acid is necessarily lost. In either case the bromide rises to the surface and is to be decanted washed with water and distilled from under aqueous solution-of carbonate of soda.The heavy layer found in the receiver is now to be carefully dried and fractionally distilled to remove traces of bromides of lower boiling points. It appears to be veiy doubtful whether the pure bromide of amyl is obtainable by treating amylic alcohol with bromine and phosphorus or by treating bromide of phosphorus with amylic alcohol. In the one case we are sure to obtain bromina- tion of the alcohol; in the other amylene or paramylene is likely to be formed. The presence of this latter compound WANELYN ON THE ATOMICITY OF SODIUM. would naturally depress the specific gravity and thus account for the error in that datum. In Limpricht’s “Organische Chemie” the sp. gr. is given as 1-1658 at Oo a result obviously considerably over 4 per cent. in error.

ISSN:0368-1769    

DOI:10.1039/JS8692200198

出版商:RSC    

年代:1869

数据来源: RSC

摘要:

WANELYN ON THE ATOMICITY OF SODIUM. XTK-On the Atomicity of Sodium. By J. A. WANKLYN. ON a former occarjion I mentioned that researches in which I had been engaged for some time on the action of sodium on alcohol led me to assign to the product of the re-action a con- stitution different from that which is ordinarily received. regard sodium as an eminently polyatomic element and I con-sider I have evidence in support of this statement. When sodium acts upon alcohol it operates upon four molecules of that body. One molecule of alcohol is attacked in its interior and the other three molecules of alcohol are joined on to the compound. The compound thus produced has tolerable stability; it is exceedingly light ; it melts at 100" C. and will bear heating to the boiling point of water without alteration.I regard its composition as follows :-C,H5O '2*!i0 Naa C2H50 c2H50 H "iI J Sodium I regard a8 septivalent. The fomda above given represents the composition of the crystals that were supposed to be ethylate of sodium. When these crystals are heated considerably above locoC. the alcohol goelj off slowly and if the compound is maintained for a long time at ZOOo all the three molecules of alcohol go off and the sodium is left in union with the residue. I believe that when this takes place the sodium invades the molecule in such a manner a8 to form the compound- WANKLYN ON THE ATOMICITY OF SODIUM. SO that the sodium is in union with the representatives of three hydrogens.I have made a number of experiments on the action of this body which I have called the absolute ethylate of sodium or hydrated oxide of ethylene-sodium. With sulphu-retted hydrogen there is first of all addition. If absolute ethylate of sodium be treated with an excess of sulphuretted hydrogen it unites with just one molecule of that body form- ing the compound- Jgc2H5 Narrr tSH This compound has considerable stability but breaks up very slowly at looointo sodium alcohol and sulphuretted hydrogen. The following compounds are obtained by treating the hydrated oxide of ethylene sodium with various reagents :-With hydrochloric acid- With chloride of aoetyl-OC H Naff'{gii36 With ethylic acetate-Na"' With ethylic valerate- b"H 0)l Na"'{ (' r&d With ethylic benzoate- All theee compounds have considerable stability but when heated to looo or 150"they decompose the second for example splitting up into sodium chloride and ethylic acetate.The President remarked that the question of the equivalent value of elements was one as to which there was at present some WANKLYN ON THE ATOMICITY OF SOI)IUM. difference of opinion. Mr. W anklyn’s views were likely to be useful if followed up by himself and others to a definite con- clusion. He thought that in many partIs of OUT progress in science %ve attend too exclusively to one particular order of phenomena without compaiing our conclusions with those derived fiom other parts of science. Until we obtain a com- pound of sodium with three monad elements we must have some hesitation in regarding that metal as a triad.At the same time he thought it quite natural to suppose that a monad such as sodium usually appears to be may in certain cases act as a triad. But it is doubtful whether it would be de- sirable to assign to sodium those functions which it appears to assume in exceptional cases rather than to say that it is a monad and explain the exceptional cases by the special hy-potheses which seem to suit them best. The combination of sodium with three equivalents of acetyl seems to favour Mr. Wanklyn’s view; but when we have three times that group acetyl (each containing two atoms of ca,rbon three of hydrogen and one atom of oxygen) a union of the elements of the three radicals amongst themselves may be conceived form-ing a radical which may itself be monadic.He (the President) thought that organic bodies must generally obey those prin- ciples which are clearly established among mineral compounds. Mr. A. Vernon Harcourt could not understand why it is not more natural to suppose that the combination of these other molecules of alcohol with what till now has been re- garded as a molecule of sodium alcohol (ethylate of sodium) should not rather be analogous to the combination of water of crystallisation with a hydrate or with any other salt. Take the caseof sodium hydrate NaHO for example. This hydrate can take up an additional quantity of water. By gradually evaporating the solution we can obtain crystals which if they contain three molecules of crystallisation-water might be represented according to Mr.Wanklyn’s views by the formula-HO HO H HO WANKLYN ON THE ATOMICITY OF SODIUM. The hydrate thus represented would be similar in composition to the new sodium alcohol and would furnish an argument though a very weak one for regarding sodium as heptatomic. A short discussion then ensued between Dr. Debus and Mr. Wanklyn aa to water of crystallisation &c. of com-pounds; after which Blr. Cha,pman said that unless we are prepared to abandon the atomicity theory we must admit that when two compounds unite they have a bond with which to hold themselves to-gether. The fact that chloride of sodium is capable of com-bining with any other compound appears to afford almost perfect proof that either chlorine or aodium-most probabIy both-is not a monad; otherwise chloride of sodium must be a perfectly saturated compound incapable of combining directly with anykhing else.After some further remarks by Dr. Debus Mr. Chapman and Mr.Newlands The President said that these words atomicity and equiva-lence had received very distinct definitions which really ought to be adhered to. The only consistent use of the word atomicity waa to denote an unchangeable kind of equivalence which waa believed by some chemists to exist. Some speakers had used the word in a very different sense that evening and he thought in one that is usually conveyed by the word equivahce. In-troducing such words as bonds he believed to be quite un- necessary because no bonds are seriouslybelieved to exkt and the habitual use of such a word must be productive of very considerable injury to the theoretical habits of those who employ it moreover no real relations of the elements are ex* pressed by the word which may not be expressed equally well without it.Whether the atomicity theory or the equivalence theory is right they are different. For his own part he thought that as a rule elements are capable under different conditions of assuming different replacing values ;but it would be going a little beyond the fact to assume that they all powess thirs capability. Still the common case is that the elements change their equivalent value and it is at all events reasonable to suppose that they all do so and by increments of two.

ISSN:0368-1769    

DOI:10.1039/JS8692200199

出版商:RSC    

年代:1869

数据来源: RSC

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203 XVTZI.-The Chemistry of the Blast-furnace. By I. LOWTHIAN BELL. THEREare many circumstances which conspire to invest the subject of iron-making with peculiar interest to the student of almost every branch of science. To the political economist after the meaw of providing food and clothing for a nation are secured it is no exaggeration to say that iron from its various applications occupies a foremost place in point of importance. Without this metal coal the very foundation of our national greatness would practically speak- ing be beyond our reach ; and not only have the great strides in facility of intercommunication of om own time been promoted by its possession but the very idea of a raiIway as at preoent existing or of driving a vessel against wind and tide conld never have suggested themselves had cheap iron not been at our command.In its manufacture a knowledge of almost every division of physical laws is constantly appealed to but it is to chemistry that the metallurgy of iron is most indebted and hence it is to the chemical philosopher that this section of our national industry most commenb itself. The position of iron as a neces8ity of civilized Iife the extent of its production along with the complicated Berim of chemical changes which accompany the treatment of its ores and the subsequent processes involved in the working of tlrira metal have attracted for it a much greater amount of attention from the chemiat than has fallen to the ahare of any other aection of the metallurgist’s art.This interest Bas been greatly magnihd by the extraordinary influence exercised by the presence of certain mbstances on the qualities of the product as well as by the extended range of character which the addition of a trifling quantity of foreign matter is capable of conferring on iron itself. We have thereby placed at our disposal this metal under three well known forrna viz. cast iron malleable iron and steel each being endowed with properties so peculiar as almost to merit so far as its own I. LOWTHIAN BELL ON THE use in the arts is concerned being regarded as a distinct metal. On being honoured by the President and Council of this Society to deliver to its members an address on some branch of applied chemistry I have selected the blast-furnace as a subject replete with interest and in the hope that the oppor- tunities I have enjoyed for many years as an iron manufacturer may justify the choice I have made.The ground to be gone over has it is true been already travelled by many distinguished chemis,ts during the last forty years but possibly it may interest those whom I have the honour of addressing to hear how far the experience of a practical smelter accords with the views of scientific men whose means of observation have necessarily Leeii more limited in their duration and character than his own. All present have probably witnessed the various operations carried on in connection with the smelting of iron in a blast-furnace. Into the throat of a great building large barrows of rough-looking materials are shot by powerful men.At the lower portion of the edifice matters are conducted upon a scale of corresponding rudeness. At three sides a roaring blast is being poured into the furnace while from the fourth running almost inceasantly is a current of highlF heated slag which is dealt with in the roughest of fashions. Generally without any protection from t,he weather the ‘6 keeper ” is occupied in moulding his L6 pigs ” in coarse sand or in maintaining his blast-pipes fi-ee from all obstruction until the time arrives when by mighty blows he drives in the tapping bar in order to afford an exit for the molten iron destined to fill t,he rude spaces prepared for its reception. When everything seems forced into obedience by intense heat or violent exertion there is one might think nothing left for milder treatment to accomplish ; yet notwithstanding all ap- pearance to the contrary there are few chemical processes requiring for their proper operation greater nicety or where perfect success iw contained within narrower limits than the smelting of iron.In a few words I may remind you that the ends sought to be accomplished in the blast furnace are the deoxidation of the peroxide of iron which is the usual form of combination in which t’he metal is delivered to the smelter its carburization and CHEMISTRY OF THE BLAST-FURNACE. fusion; accompanying this is the expulsion of carbonic acid from the limestone and the union of the lime it contains with the earthy matters associated with the ore and fuel to form a fusible slag.In this brief description the fuel employed is supposed to be coke or charcoal; for should raw coal be used the hydrocarbons arid other volatile constituents emitted on the application of heat may be left out as forming no necessary part of the process we are about to consider. The circumstance of the different stages of the operation to which allusion has just been made being effected at different temperatures has led some chemists to divide the interior of the blast furnace into a certain number of spaces or regions and designate them according to the character of the action which was supposed to be carried on therein. Sche erer among others assigns a distinct zone in which he imagines that.each of the various steps of the process of smelting is more or less effected. The uppermost one he calls the warming zone in which the ascending current of gases imparts a portion of its heat to the materials just entering the furnace ; the second is the reducing zone where the oxide of iron begins to part with its oxygen and in which also the carbonic acid of the limestone is expelled; in the third carbon is supposed to unite with the iron which along with the earthy constituents of the materials is melted in the fourth or zone of fimion by means of the intense heat given off immediately below in the fifth or zone of combustion. It is into the last zone that the blast is admitted the oxygen of which is almost instantaneously converted into carbonic acid which gas coming in contact with incandescent coke or char-coal as the case may be generates carbonic oxide to serve as the reducing agent in the upper portion of the furnace.The annexed figure will convey an idea of the manner in which Scheerer conceived the interior of a furnace was divided and the space he allotted to each division of the opera- tion and alongside of it is placed a diagram indicating the supposed increase of temperature. More recently Professor Tunner of Leoben has by means of different alloys and various metals attempted to determine the temperatures of two furnaces in Carinthia and this distinguished metallurgical chemist further endeavoured to ascertain by actual exposure of ore at different depths of the furnace the exact I.LOWTHIAN BELL ON THE point at which reduction began and the various degrees of rapidity with which it was effected. Th he accomplished by S(IHPE BEB. Warming Zone. &om top. Depth 12 feet. Reducing Zone. from top. Depth 17 feet. Carhrizing Zone. fiom top. Depth 9 feet. Zone of &-&on. from top. Depth 6 feet. Zone of Combustim. Depth 4 feet. employing a small iron box with the top and bottom provided with apertures SO that a portion of the gaseous contents of the furnace pamdng through its interior might heat and then deoxidize any ore placed tlherein. This apparatus was introduced into the fixmace,and permitted to descend to different depth along with the usual materials and was then drawn up by means of a windlass.A series of such trials led to the Professor laying down a diagram of the rate of reduction observed which it would appear barely com- menced at a temperature of 680' C. (1265 F.) The sketch here is copied fiom Professor Tunner'e descrip- tion of the experiments he conducted. In the figurethe line a b C marks his ascertained zone of reduction and d e f the region of carburization. Alongside of it is a diagram compiled fkom his results to show the different temperatures at various depths ofthe furnace BB obtained by means of the alloys and metals the fusing points of which were previously ascertained. It will be observed that Professor Tunner marks a depth of about 20 feet fkom the throat as the commencement of the prooew of reduction which wae reached 70 minutes after the CHEMISTRY OF THE BLAST-FURNACE.ore was introduced into the furnace and at which the tempera-ture was as high as 700’ C. (1292 F.) TUXNER Commencement of redactioni Commencement of carburization. EBELYEX. I am not acquainted with the means Scheerer employed to obtain the data upon which he constructed his diagram but it will be observed there is a marked difference between the views of thia chemist and those just described. Upon Scheerer’s figure I have laid down for the sake of comparison the curved lines a 6 e and d e 5 to mark the beginning of the reducing and car- burizing zones according to the piin-ciple adopted by Professor Tunner.Ebelmen at Clerval in France by means of apparatus similar to that em- ployed by Tunner asoertained that reduction commenced at a depth of 8.2 feet from the top after the ore had been two hours in the furnace and that it was completed at a depth of 18.9 feet 208 I. LOWTHIAN BELL ON THE from the throat after an exposure of 6 hours 25 minutes by which time incipient fusion had set in. The line a b c repre-sents in the adjoining sketch the rate of reduction as observed by Ebelrnen and d 4 f will be something like the upper limit of his supposed zone of carburization. My own experience leads me to question whether any such lines of demarcation as those described by the authorities just quoted can be laid down in any blast furnace because to do this within any reasonable limits would require that each frag- ment of ironstone is descending with the same speed a8 all those introduced at the same time and that every piece is susceptible of being deoxidized a8 rapidly as the remainder.Now neither of these aonditions prevails on the contrary the very reverse iR known to take place. The friction of the materials against the sides of the furnace particularly when they reach the slopes immediately above the tuyeres retards consider- ably the descent of those portions exposed to its influence. This is a recognized fict within the observation of every furnace manager who knows that any change in the relat8ive propor- tions of the minerals does not make its presence felt at the lower part of the furnace with all the suddenness with which it was made at the top; but the alteration in the working takes plme somewhat gradually as if the first charges of the change presented the apex of a cone something in the manner of the curved lines in the annexed ideal section.The uniform motion of the mass downward is fiirther liable to considerable disturbance by the smaller pieces of ironstone outrunning the larger by slipping through openings in the contents of the furnace a mode of progress which cannot happen with those of larger dimensions. The correctness of this supposed iuterference of a uniform downward motion of the materials in a blast furnace was con-firmed experimentally by the elder T uririer who filled one with a given quantity of charcoal before he put in any ore and also at the same time placed in different positions in a given hori-zontal section pieces of marked wood.Instead of lighting the ftirnace when it was thus filled to the top Tunner drew out CHEMISTRY OF THE BLAST-FURNACE. its contents by manual labour by which means he ascertained that portions of the ore arrived at the bottom in little more than one-third of the time occupied by the charcoal introduced at the same period. In like manner the marked pieces of wood placed near the middle of the furnace came down much more rapidly than those which had been retarded by rubbing against the wall of the structure. Again the size of the pieces of ironstone exercises a marked influence on the rapidity of the chemical action which the oxide of iron has to undergo during its passage through the upper portion of the furnace supposing therefore two pieces of ore to be travelling side by side one containing a cubic inch of matter and the other a cubic foot the metal in the former will be nearly perfectly reduced almost before any action has commenced on its neighbour.In like manner the expulsion of the carbonic acid from trhe limestone will be greatly retarded by the size in which this mineral is employed in the process of smelting. The same delayed action will happen if a considerable quantity of sindl material is permitted to accumulate in a given portion of the interior of the furnace; indeed there is perhaps no cir-cumstaiice which more frequently deranges the operation than this unless special precautions are adopted to prevent its occur-rence.Tipping the materials into one side of a furnace by which the greater portion of the fuel and the larger pieces of ore and limestone run to that opposite never fails to act ig a most prejudicial manner. I have seen furnaces have their weekly make increased by nearly one-half and their consump- tion of fuel economized to an extent of 30 per cent. by simply altering the mode of charging. Upon another occasion the throat of a furnace was reduced fi-om a diameter of 4+feet to one of 3 feet. The effect of this was concentrating as it were the smaller pieces into a column ; because as soon as the materials reached the wider part of the furnace the larger fragulents would roll to the outside.This column more or less unbroken would descend to the hearth and from its impervious character in an imperfectly deoxidized condition. This gives rise to a cooling action in that part of the furnace where the heat is required to be the most intense and unreduced oxide of iron acting as a base enters into the composition of the slag and thus causes a loss of metal as we11 as a deterioration in the quality of the product. It is perhaps worthF of remark VOL. XXIT. R r. LOWTHUN BBLL ON THE that a temperature represented by 2,000 units per minute meording to the French scale is sufficient to reduce the quality of the iron one number in the scale.When it is remembered that this represents only about two pounds of coke the amer- tion that the smelting of iron in spite of its apparent roughness is a rromewhart delicate operation will scarcely be considered as an exaggeration. The information which is sought to be obtained respecting the temperature of the different sections of a furnace is att.ended necessarily with considerable difficulty. The materials which occupy the interior are difficult of penetration and the tempera- ture itself is so high. as to oEer serious obstacles to its estima- tion; there are besides constant changes in the character of the chemical action which necessarily will cause corresponding changes in the temperature of any particular locality. These variations may be increased from alterations in the direction of‘ the current of heated gases a8 they meet with greater or leas opposition to their progress and the nature of the he1 itself may by the increased power its texture may confer on it of decomposing carbonic acid all tend to complicate the question.Tunner and Ebelmen’s mode of judging of the rate of the reduction might be accepted as an indication of what it is under the most favourable circumstances as to size inasmuch as in their apparatus of limited capacity they only introduced pieces of ore having very small dimensions. The very circumstance however of the mineral being encased within a box introduce8 an element of difference between the samples under experiment and those in the furnace.My own observation would indicate that the oxide of iron when exposed to the unimpeded action of the gases of a blast furnace is reduced at a temperature con-siderably below that assigned by any of the authorities already referred to and further that the rapidity of the process is mate-i-jally interfered with by any protection like that involved in the use of such a vessel as that described by Messm. Tunner and Ebelmen. I will now as briefly as possible give you the reasons founded on actual experiment which have led me to adopt opinions in reference to this portion of the action of a blast furnace which are at variance with those of others whose writings I have consulted as containing the latest observation on the subject. It may be remarked in the first instance that the material CHEM€$TR'Y OF TEE BUST-PURNACE.ope-td upon wag the ironatone of Clevehd but in order to ascertain to what extent previous experimenters had obtained results differing from my own by the use of other varieties of ores specimens of red and brown hematiices and spathose ore were subjected to the same mode of treatment as that pursued with the stone smelted in our own furnaces. In order to form some judgment of the temperature and rapidity with which the oxide of iron in the calcined oolitic knstone of Cleveland was reduced by means of carbonic oxide a glass tube was filled with pieces about the size of hemp-seed and heated short of redness probably about 300 C. (600 F.) In this state a stream of carbonic oxide was passed over it and the resulting gas collected and examined.It contained 96 per cent. of carbonic acid showing that a very small proportion of the original gas had escaped unchanged by the oxide of iron. A portion 80 treated was then examined and found to have in the space of 15 minutes lost 39 per cent. of its oxygen. After this a very large number of specimens of caloined iron- stone were exposed at various times to the escaping gases of the furnaces at the Clarence Iron Works for periods fbm one to ninety-six hours. The furnaces vary in height from 48 to 80 feet with a capacity of about 6,000 to 26,000 cubic feet. As might be expected +he escaping gaees differ in temperature according to the dimensions of the furnace-those horn the larger being cooler by their passage through a greater quan- tity of sdid material before they reach the top where the out- jet is placed.The ironstone broken to about the size of hazel mt8 was placed about 6 or 8 feet from the furnace in the tube for conducting the gas to the boilers and hot-air stoves. The commencement and termination of the process of reduc-tion it will be recollected was given as follows :-Began. Ended. By Scheerer ..... . .. 400 C. ('752" F.) 1000 to 1200 C. = (1832 to 2192) F. ,,Tunner .. .. .... .. 680 (1256) 1400 = (2552 F.) , Ebelmen . . . . . .. Below red heat Incipient fusion of ore. If then it can be shown t.hat the temperatures of the escaping gaserJ at the Clarence furnaces rarely exceeded the lowest of these and frequently were considerably below that it follows if these figures are correct that little and in most cases no oxide of iron could have been reduced when exposed to their influence.R2 L LOWTHIAN BELL ON THE The specimens previously thoroughly dried were examined for iron before and after exposure and the difference would enable us to estimate the loss of oxygen should any take place. The following table will afford at a glance the results of these trials among which there occurs only one single instance in which no change in the composition as regards oxygen appears to have been effected :--Indications of Temp .% Q)&22 E3& - i+ 5d -$8 Ge - -i 44v i?g- &-::3 0" g.840 2 6 'I 4 2 7 6 4 6 2 7 4 4 9Y ?? 6 4 6 4 6 4 6 4 2 4 11,600 26,500 16,400 6,000 11,600 15,400 26,500 6,000 26,500 11.600 15,400 6,000 #? tY ?) 26,500 6,OGO 26,500 6,000 26,500 6,000 26,500 6,000 11,600 26,500 1 1 1 1 2 2 2 2 3 3 3 3 6 12 18 24 24 48 48 72 72 96 96 24 24 After dinner hour Includes dinner hour ; no charging.Furnaces all quite full. Trial continuous. Re-cord of temperaturemean8 since each pre- ceding observation. Trial continuous atI each furnace sample8 exposed in a per-forated box. I I } sample on tmy. Bi Bi Bi Pb Bi Bi Bi Pb Bi Bi Bi Pb Zn Stb Zn Pb Zn Pb Zn Pb Stb Bi Stb Pb Pb Pb Pb Pb Pb Pb Pb Stb Stb Tot recorded Pb Zn Zn Zn Y; ?# ?I p'i,Zn Zn Stb )? Zn Zn Stb Zn Pb pro-bablymelting pointof Stb. 4 -20 5,31 4 -20 5 '31 4 -76 4 -75 6 '10 11 '83 0 -00 '97 4 *76 6 -10 50 *51 62 -66 68 *19 3 92 35 5-7 5 -71 48 -83 27-82 54.02 27 *16 57 .I2 53 -64 100 *oo ~~ ~~~~ It is only right to remark that partly from a little dust being liable to be deposited on the specimens during exposure and partly from other cawes which will be hereafter spoken of a8 adding to the weight the result given in the column showing the loss of oxygen is rather under than overstated.Conceding that the gases from the largest furnace are the coolest as really happens and those from the smallest the hottest the deoxidntion aa might be expected is the moat CHEMISTRY OF THE BUST-FURNACE. vigorous fiom the furnace of the least dimensions and generally speaking decreases with each addition to the capacity. It will also be observed that where the fragments of ironstone were placed not on an open tray but in a perforated box some-thing after the method pursued by Messrs.Tunner and Ebel- rn en the amount of reduction was sensibly interfered with. In the instance of the last sample mentioned in the list where all the oxygen was removed the gas given off by the addition of hydrochloric acid was found to be entirely hydrogen with the exception of a small quantity of carbonic acid which existed in the ore previous to exposure. On examining the composition of the gases taken from that part of the Wrbna furnace where according to the former gentleman deoxidation first manifests itself it was noticed that they contained a very much smaller proportion of the reducing agent viz.,carbonic oxide than those to which the samples had been exposed at the Clarence works; and as this difference might possibly affect the rate of the action on the ore 15 litres of a mixture was prepared resembling 80 far as carbonic oxide carbonic acid and nitrogen are concerned the composition of the Wrbna gases and a similar quantity corresponding in respect to these substances with the gases of the Clarence furnaces.* These quantities were separately passed over Cleveland calcined ironstone in 1 hour and 45 minutes in one case and in 1hour and 50 minutes in the other.During the progress of the experiments twelve samples of each were collected and tried for carbonic acid. From that resembling the gmes in Professor Tu nn er 's investigations the average volume of car-bonic acid was 28.4 per cent.of the whole and in the case of the gases of the Clarence furnaces 35.7 of the total vo1ume.t Both * Compoeition of gases used in experiment by volume :-COHl COZ N Wrbna ................ 13 16 71 = 100 Clarence.. .............. 32 6 62 = 100 I-Volume per cent. of carbonic acid. Particulars of twelve trials:-Wrbna .. 27.4 28.4 per cent. Clarence.. .. 32.6 34.9 per cent. J) ) .... 28-4 28.1 ,) .... 34'9 33.9 ,* JJ .... 27.9 27.9 ) , .... 36.8 36-0 .... 28.9 28.6 J J2 .... 37-36'0 , ,) .... 29. 28.8 , ) .... 38' 36.0 ,) , .... 29-28.6 , as ..,. 37.4 36.0 , ¶ I. LOWTEIAN BELL ON THE of thege results indicate almost complete conversion of carbonic oxide into carbonic acid but of the two the Wrbna mixture is a trifle more perfect proving thus that the want of power of deoxidation was not due to its lesser proportion of carbonic oxide.The next point to be ascertained was whether the Cleveland ironstoile wa0 not more susceptible of the deoxidizing power of the furnace gases than ores generally are found to be. For thk purpose a specimen of red ore of a very close grain was selected &om Weilburg a brown ore from Wetzler and a Spathose one from Herdorf. They were calcined to drive off water and carbonic acid and then exposed for 7+ hours in the escaping gases of No. 2 furnace at the Clarence works. This furnace has a cubic capacity of 11,600 feet and in two hours had upon a previous occasion expelled about 5 per cent. of the oxygen con- tained in the calcined Cleveland stone.In the 7+ hours the Weilburg red ore lost 11.99 per cent. of its oxygen and the Wetzler brown ore 16-88; the Spathoee ore was also evidently acted upon but to what extent has not yet been determined. The larger pieces of ironstone which are here exhibited after an exposure of 24 hours to the gases of blast-furnaces prove that although mass may retard the action and even delay its commencement until snfficient heat has been imparted a t'emperature considerably below that stated by the distin-guished foreign chemists whose names have been given is rJufficient to completely deoxidize ores of iron. No doubt for this time is reqnired but partial reduction appears to be effected much more quickly than their observations would lead us to suppose.Although we have hitherto been consideling carbonic oxide as the sole reducing agent in the gases of the blast-furnace there are three other substances often found associated with it which are also capable of removing oxygen fiom the compound this element form8 with iron. They are hydrogen cyanogen and ammonia. In the caae of a furnace employing well burnt coke from which the hydrocarbons are completely volatilized by the coking process the only source of hydrogen will be the hygro- metric moisture diiven in with the blast for all water which may be present in the materials in we will probably be expelled before it arrives at a depth where the temperature is suffisiently CBEMISTRY OF THE BLAST-FURNACE.elevated to effect its decomposition. In charcml circurnstancm are different for Bunsen found in it 2 to 3 per cent. of hydrogen which was only completely expelled on the appli- cation of a white heat. I believe the generally received opinion is that notwith-standing the strong aEnity which hydrogen has for oxygen and the extreme readiness with which it abstracts this latter gas from its combination witlh iron it plays no part as a reducing agent in the blast-furnace. Although according to Nagnus its reducing power over oxide of iron commences at 360' (670' I?.) it would seem if the supposition of its inertness in the blast- furnace be correct that the presence of so large a quantity of carbonic oxide found there must interfere with the exercise of its action on the iron ore.Almost all the analyses which I have consulted exhibit a gradual increase in hydrogen towards the mouth of the furnace as if the gradual rise in heat which the charcoal meets in descending expelled this gas without its being altered by contact with the oxide of iron heated although the latter was to a point to admit of its reduc-tion by hydrogen. With regard to cyanogen this substance is obvioudy generated by the presence .of tJoda and potash producing cyanides of the metallic bases of these alkalies by determining the union of carbon and nitrogen. The formation however of cyanogen by no means appears to be an invariable conse-quence of the existence of these alkalies for I have before me a sample of a mixture of the two which was collected near the tuyeres of one of the Clarence furnaces and in it no cyanogen appears to be present.Messrs. Bunsen and Playfair in their celebrated report to the British Association assigned an important part to the reducing agency ofs this compound. Dr. Percy mentions that the propor'iion in which cyanogen occurred in the blast-furnace at Alfreton the scene of their experiments was so small that it; was only equal to reducing 3-75 per cent. of the make. This furnace is only 39.4 feet high and the only place where cyanogen waa detected by these chemiats mas 34 feet from the top a point where judging fi-om that which has pre- ceded there ought to have been no oxide of iron requiring reduction. The fact of the disappearance of the cyanogen almost im- 216 I.LOWTHIAN BELL ON THE mediately after its production can be probably accounted for on other grounds than its supposed action on oxide of iron. I found that one volume of it mixed with two volumes of carbonic acid and passed over quartz pebbles heated to redness in a green glass tube was decomposed with deposition of carbon. It is true nevertheless that the mixture of these two gases in the proportions given wa8 found capable of removing oxygen fioin oxide of iron for in 15minutes calcinedcleveland stone lost 3.42 per cent. of its oxygen at a temperature short of redness and when the heat was raised until the glass softened 25-14 per cent. of the original oxygen was expelled. The only instance in which ammonia ever came under my notice iu a blast-furnace was in the form of chloride which dropped associated with other salts and water from the gae tube upon the occasion of using raw instead of calcined iron- stone by which the temperature of the escaping gases was reduced to about 40° C.(104 F.)* At a temperature short of redness ammoniacal gas was ascertained to deprive Cleveland calcined ironstone of 2.85 per cent. of its original oxygen and at a low red heat 17.71 was expelled. In each caBe the operation was continued for twelve minutes free ammonia escaping from the open end of the tube. Whether this alkali ever exists in a condition to enable it to act a8 a reducing medium in a blast-furnace I am unable to say ; one thing however may be accepted as certain viz.that the quantity is never such as to render its action of any importance in the operation of iron smelting nor shall we be far wrong in assuming that for all practical purposes carbonic oxide is the sole reducing agent to which must be referred the duty of deoxi- dizing the ores of iron in the furnace. During the passage of the reduced iron through the furnace and under the influence of the high temperature to which it is exposed on its way to the hearth the metral is apt to carry down some of those substitnces with which it was originally aesociated in itrj ore or which it meets with in the flux or fuel employed. To such an extent may thipr occur that FreBeniusr * Composition of the substance was as follows :- Insoluble.Chloride Chloride Chloride Water. ammonium. iron. Zinc. 1.0 62.9 147 6.6 24.8 = 100 CHEMISTRY OF THE BLAST-FURNACE. quotes a case in which he detected and estimated the quantity of not less than twenty substances other than iron in a specimen he analyzed. In some cases as much as 22 per cent. of man- ganese has been found ia pig iron and above 5 per cent. of silicon the presence of the former due to the ore employed being rich in that metal and the latter derived probably from the temperature of the furnace being high enough to decompose the silica invari- ably present in the materials under treatment in a blast-fiirnace. That neither of these elements nor all the others mentioned by Fresenius with one exception are essential constituents of pig iron is proved by the circumstance that although no cases perhaps are known where none occur every one or other is occasionally absent.The one exception is carbon which may therefore be looked upon as a necessary ingredient of all pig iron. The circumstances which determine the union of this in- dispensable element with the metal are of high interest to the smelter because upon the condition in which the carbon is associated with the iron depends it is considered the different qualities of the article he is manufacturing. The portion of the fiirnatce in which the combination takes place the temperature necessary for effecting it and the exact source of immediate supply have engaged the attention of all chemists who have studied the subject.Scheerer assigns to it something like the position described by the line d. e. f.in his section where the operation he states is effected after all traces of unreduced oxide have dis- appeared and where the temperature ranges from l,OOoo to 1,600' C. (1,832' to 2,912' F.) Tnnner by means of his perforated box containing frag- ments of calcined ore determined that carburization did not take place until a depth of 29.8 ft. fiom the top of the furnace was reached where the temperature ranged about 1,150O C. (2,1.02"F). This patient investigator indeed deduces fi-om the known heat at which carbon unites with iron in the process of cementation the temperature of this portion of the himace which he states accords with what it ought to be fiom a direct observation made 4-33 feet higher up.He further lays down the limits of the zone marked d. 8.f. on his section in which the union of the carbon with iron is accomplished. Upon the sketch intended to show Ebelmen's idea of the I. LOWTEUAN BELL ON THE EOTM of reduction and carburization the latter ia somewhat higher up but according to his views no signs of it were apparent until the wrought iron apparatus was softened by the beat and the ore itself manilested symptoms of incipient fusion. The conditions then deemed essential by these three gentle- men were reduction almost if not perfectly complete and a tem-perature of something like l,OOOoto 1,200' C. (1,832' to 2,192' F.) Let us now enquire whether it is not highly probable that the exclusion of the full force of the chemical energy which the gaaee of the fwnace were capable of exercising by confining the ore in a box has not interfered with the action of carbnrizing in the lsame way asl happened in all probability with that of de-oxidizing.In order to ascertain the extent of the change in content of iron the samples were after exposure dissolved in hydrochloric acid a mode of procedure which afforded of course an insoluble residuum. When a sample of calcined ironstone was exposed for the space of two hours in the waste gases of any of the furnaces large or small this residuum was of a colour inclining to grey- not calling for any rJpecial notice. The same may be said when the exposure was carried on for three hours in all the Furnaces except those of the least dimensions fiom which as we have already seen the gases issue the hottest-zinc in them fre- quently melting and occasioiially antimony.In a hrnace of this type such as No. 4 at the Clarence works the insoluble residuum under consideration from a specimen after three hours' contact with the hot gases was blackish and this coloixr went on increasing in intensity as the exposure was prolonged until it became perfectly black. On the other hand No. 6 furnace having above four and a half times the capacity of No. 4,or 26,500 cubic feet instead of 6,000 never gave off its gmes during a period of observation extending over 96 hours hot enough to melt zinc; for during 72 hours of this time lead melted and for the last 24 hours bismuth only was fused.Ironstone exposed during these 96 hours only afforded a grcyish insoluble residuum on being treated with hydrochloric acid. These observations have led me to conclude that an exposure of three houra to a temperature a little above the melting point of lead and below that of zinc sufficed to give the black CHEXBISTRY OF THE BLAf4T4"FiNACE. CO~OW whereas at about the temperature at which lead fuses no period up to 96 hoiws mfficed to produce it. Probably if we give 337" C. (630 Fa),as being below the heat necessary to give the blackness and 361" C. (700"F.) equal to afford it we shall not be wide of the truth. On examining ineo the came of this blackening it was found to consist of carbon inasmuch as it -kota!ly disappeared on the residuum being heated in eontact with air and on passing a current of pure oxygen over it vkid combusLion was produced and carbonic acid generated which was recognized in the nsuaf way.This carbon moreover exists in such a minute state of division as to induce me to believe that it is really combined with the iron or is deposited by chemical action in such a form ag to present great facilities for subsequent combination. It there-fore seems probable that instead of the lowest and hottest portion of the furnace being the zone of carburization this change occurs high up where the temperature is comparatively low. Neither does it appear that anything approaching to complete deoxida- tion is required; for in one case where only 6-10 per cent.of the oxygen of the ore was driven 06the residuum was blackish and with anything like 50 per cent. of loss of oxygen the colour is intensely black. On the other hand oxygen may be removed to the extent at all evefits of 28 per cent. and no strongly marked signs of carbon appear in the residuum if the heat during exposure has not reached the necessary point of elevation. The amount of carbon associa,ted with the iron was deter- mined in those cases where the exposure of the ore had been effected in a box with perforated sides and open at the top. The residuum from ore arCter 48 honrs' exposure lost 48-83per cent. of its oxygep and contained of the weight of iron .. .* .. 2.42 C.per cent. 72 hours' exposure lost 54.02 per cent. of its oxygen and contained of the weight of iron . . .. .. 309 c. , while in another instance where the ore was placed on an open tray all the oxygen was gone and carbon to the extent of 3-26 per cent. of the weight of iron was found in the re-siduum." * Time did not permit the necessary analysis being made 80 as to obtain with assess the whole af the carbon. To estimate the iron 8 solution in hydroohloric 220 I. LOWTHIAN BELL ON THE It may be observed that the residuum from all the samples of foreign ores exposed for seven and a half hours in the gases from a furnace of medium size showed unmistnkeable signs of carbon having been deposited. Admitting the correctness of the opinion just laid down the following formula would account for the action when the de-oxidation and carburization is complete :-8 CO + 2 Fe,O = 7 CO + 4 FeC.I am however by no means satisfied that this equation conveys a true explanation of the action for within the last few days I was desirous of ascertaining how far the introduction of the Cleveland ironstone in its raw state i.e. as carbonate of iron would retard the deoxidation. The extent of this is immaterial but what is of importance is that a very considerable increase in the quantity of this deposited carbon took place in each sample exposed. Here are five specimens of each Biz. the insoluble from the ironstone raw and calcined before they were placed in the escaping gases of No.4 furnace the others being the insoluble and blackened residuum after the two varieties exposed at the same time had been in for 6 12 18 and 24 hours. In the case of the raw ironstone the colour was so much blacker than when the calcined ore was used that the quantity of carbon in each was carefully determined. With the calcined ore it amounts to 1.68 per cent. of the iron while in the raw stone it is 4.63 per cent. of the iron after each had been exposed 24 hours in the escaping gases.* wid wm made during which probably a portion of the carbon was lost and I m obliged to content myself with examining the insoluble left after treating the samples with this acid. * a. Insoluble from 100 grains of calcined ironstone in which organic matter must have been destroyed was dried at 193 C.(380 F.) :-Heated to redness in contact with air lost.. . . . . . . . . . a . . . . 0.16 gr. 6. Insoluble from 100 grains of calcined ironstone same as above previously exposed i? waste gases of No. 4 Clarence furnace for twenty-four hours :-Dried at 193 C. (380 F.) and then heated to redness lost.. . . . . . *88gr. Deduct for loss assumed as independent of carbon.. . . . . . . . . . . -16 ,, -Leaving for carbon . . . . . . . ,. . . . . . . . . . . . . . . . . . . . . . . . . . . ‘13 gr. Specimens contained 43.5 per cent. of iron. Carbon therefore is equal to 1.68 per oent. C. Jnsoluble from raw ironstone exposed as such in gaaea from No. 4 Clarence CHEMISTRY OF THE BLAST-FURNACE. It wa8 then deemed desirable to ascertain to what extent carbon might be caused by any organic matter existing naturallyin the ore and retained in the ironstone while the latter was imperfectly calcined and consequently before the carbon so formed was entirely burnt off.When the insoluble residuum from this source was thrown into melted nitrate of’ potash the faintest trace of carbon made itself apparent whereas with that obtained in either of the two instances previously quoted deflagration of some violence was produced. In the minds of all practical smelters there is no doubt enter- tained that the hotter a fimace is working the richer is the iron in graphitic carbon or “kish,” as they term it. This together with the circumstance that when the temperature is very high flakes of this substance escape in considerable quan- tities when an opening is made a,bove the dam of the furnace probably has favoured the belief that the region of fusion wag the chief seat in which.the union of carbon with the iron was accomplished. It is perhaps a little premature to speculate upon the nature of the origin of carbon in pig iron by aid of facts many of which have only been ascertained since this paper was begin and some investigated so lately as yesterday. It may how- ever be observed that although this substance exists in pig iron in two distiiict forms viz. as combined and as uncom-bined or graphitic there is nothing antagonistic in the idea of‘ carbon uniting with iron in that portion of a furnace where no such difference of temperature is ever found likely to produce at one time white iron in which the carbon is chiefly in the com- bined form and at other time grey iron rich in uncombined carbon.It is I imagine quite consistent with all observation to suppose that the ore during or after the process of reduction may absorb all the carbon it requires but the form this element furnace for twenty-four hours. Insoluble from 100 grains of the ironstone weighed after exposure :-Dried at 193 C. (380 F.)and then heated to redness lost.. ..,. 1-90gr. Deduct for loss assumed as independent of carbon ............ -15 , Leaving for carbon .................................... 1-75 Sample contained 37’8 per cent. of iron hence iron is associated with 4‘63 per cent.my WSX~IIPB in the pig iron pmduced will depend on the tam-perahre when fiisim takes place. This explanation is corm+ borated by the well known fact that whits iron may be run &om the blast furnace and be changed to grey by slow oooling and the richest No. 1 iron may be reduced to No. 3 or even mndered white by chilling it suddenIy against a surface of cold metal proving thus that it is the latest condition of thine previous to solidifimtion which determines the character of the earbon rather than the mode in which it hae found its way into the metal. As to the flakes of kilsh"flying about a furnace making I' rich iron it is possible they may be produced by the decom- position ofthe oxides of carbon under the influence of the high temperature and chemical action or even by the decomposition of cyanogen for I ascertained that this compound not only depoaited carbon when heated along with carbonic acid but thatit also at a temperature of redness conferred caxbon upon iron of which it had effected the reduction.A consideration of the other occasional constituents of pig iron would carry us far beyond the limits of such a discourse as the present ; we will therefore pass on to review in as con-densed a manner as pos~ible the behaviour of lime in the blast- furnace. One duty but not the only one performed by this earth generally added in the form of its carbonate is to act as a flux by melting and separating the solid impurities or" the ore under treatment. The labours of Berthier informed us how the fusibility of any two earthy substances was promoted by the addition of a third and what an extended range of pro-portions could then be used without seriously interfei+ with readiness of fusion.This chemist further showed how the presence of a fourth or more substances even in very small quantities augmented fusibility. Were it not for these laws the smelting of many of our ores would be a matter of great diEculty if not of impossibility owing to the endless variety of the proportions in which silica alumina lime and mag- nesia are found associated with the metal. Dealing with these earths alone silica occurs in every pro- portion from 30 to 70 per cent. of the whole alumina from 24) to 30 per cent. lime from 4 to 27 per cent.and magnesia CHF'WFRY OF THE BLAST4"UACE. firom 3 to 19 per cent. and &his bt merely comprehends msne of the orby ironstones ofthi8 country.* It ia usually considered that the use of an excess of lime promotw the separation of sulphur and it may be of phospboi-tq from the iron produced for it is frequently added when the earths naturally existing in the ironstone are in such yro-portions aR to coustitutea perfectly fusible slag. This is the cage with the ore olCCleveland as was proved by actual experi-ment in the laboratory after which one of the Clarence furnaces had lime gradually removed from the charges uniil it warJ entirely withdrawn. So far as the mere oEce of smelting was concerned the operation waR peifect ie.all the iron existing in the ironsxone was obtained and a perfect slag wals produced. There wag some little practical difficulty connected with working the furnace but the inconvenience which waa anticipated occurred,-the iron No. 3 contained much more dphlrr than when using lime viz. 0.33 per cent. and it,^ quality in point of strength suffered considerable deteri0ration.f It will be impossible for us upon the present occasion to dwell at any length upon the distinctive characters which mark blast- * Proportions in which silica alumina lime and magnesia exist in certain iron- stones calculated from analyses contained in geological survey of Great Britrrin. 100 parta consist of Silica. Alumina Lime. Magnesia. Darlaston.. ...... 69 24 4 3 Dudley.......... 61 29 5 5 Low Moor ....... 60 24 9 7 Corngreaves.. .... 59 28 a 5 Rough Hay ...... 58 20 11 11 Butterley.. ...... 55 24 10 I1 Dudley.. ........ 53 28 13 6 Dowlais.. ........ 62 23 12 18 Blaenavon ....... 50 21 12 17 Stanton.. ........ 50 20 12 18 Blaenavon ...... 49 25 a 18 Staveley ........ 49 25 7 39 Parkgate ........ 44 24 13 19 Dowlais.. ........ 39 27 15 19 Cleveland ........ 31 29 27 13 .). Sulphur in Clarence iron :-No. 1iron ....... -04 per cent. No. 3.. .... -10per cent. Do. ....... -25 , Do. ...... -17 , Do. ....... trace Do. ...... -04 , Vide Paper by I. L. Bell on Cleveland Iron Manufacture read before British Aaso-eiation at Newcastle 1863. I. LOWTHIAN BELL ON TD furnace dags which have compositions embracing BO extensive a range of variations in their constituent parts.This interest- ing series of compounds occasionally when silica is in sufficient quantity possessea the properties of true glass gradually chang- ing into substances of a perfectly stony nature in which no trace of vitrification is usually perceptible. This is particularly the case when alumina is in such quantity as probably to divide with silica the functions of an acid. Mention has already been made of the difficulty which accom- panies drawing any general conclusions respecting the progress of the operation of smelting from an examination and analysis of the solid contents of a blast-furnace. Probably the most elaborate investigations into the nature of the gases taken from various depths of a blast-furnace are contained in the communication by Messrs.Buns en and Play fair to the British Association in 1845. Judging from the drawing which accompanies the paper the furnace at Alfreton was charged in the defective way already spoken of viz. at one side only of the throat. It may therefore be ques- tioned whether the current of gaseous matter would have any- thing like a uniform composition over any horizont,al section corresponding with the point where the samples were taken. Dr. Percy in his review of the various analyses made by different chemists despair6 of being able to elicit any general expressions by which the chemical action of each portion of the blast-furnace can be explained and it is to be apprehended this is a state of ignorance in which we must be content to remain.Imagine a furnace in which pure oxide of iroii is being smelted by pure carbon ; now so long as the oxide was reduced in the upper and cooler portions the extent of carbonic acid would be a correct indicatiou of the nature of the process carried on; but wherever deoxidation is delayed as no doubt may happen until that depth is reached when the high tem- perature would decompose this acid then the gases afford no indication of the change effected on the solid contents of the furnace. When we come to consider the properties of carbonate of lime when exposed to heat in an atmosphere of carbonic acid the problem of drawing from the presence of this gas any general inference of the chemical alteration going on in a furnace becomes very intricate if indeed not impossible.CHEMISTRY OF THE BLAST-FURNACE. Thirj salt of lime as is well known parts with half its car-bonic acid at a moderate red heat a much higher temperature being required before the whole is expelled. In the solution of the question just mentioned we have to determine not only whether all the iron is deoxidized but also whether the tem- perature is such as will drive off carbonic aiid from the limestone and then whether the heat is sufficiently high to decompose the carbonic acid from either source. In the case of the ore it is quite possible that all the carbonic acid resulting from its decomposition may be formed when this change would be impossible ; but in that of the limestone it is pretty clear the last half more or less will not be set free until meeting with hot carbon it is instantly resolved into carbonic oxide.It is by no means an uncoinmon thing for iron smelters to use caustic lime in their operations ; this however does not simplify the inquiry but rather the reverse. Up to a temperature of redness such as to soften green glass I ascertained that lime absorbed carbonic acid in proportion to the temperature to which it was exposed i.e. the higher the heat the more rapid was the union-this absorption went on until 19 per cent. of the weight of the lime was taken up after which a stream of the gas continued for nine hours produced no further change.On the other hand carbonate of lime and caustic lime were subjected to a current of carbonic acid in a porcelain tube and heated until the latter began to soften. In this case there wag no absorption of carbonic acid on the contrary all the acid was driven off from the carbonate. So far as moderate temperatures are conceriied it was ascer- tained that caustic lime rapidly absorbs carbonic acid from the escaping gases," so that in addition to not knowing the rate at * Caustic lime exposed for one hour in escaping gases from No. 4 Clarence furnace :-Lead melted zinc not changed absorbed of its weight of C02 .. . . ,...... . ... .. . ,... . ,.. .. . . . . .... . . 1'28 per cent. No.'7 furnace Bismuth melted lead not changed . . ... . , 1-00 , 2 furnace ditto ditto .... .... '96 , , 6 furnace ditto ditto ........ *92 ? After two hours' exposure temperatures as above :-Lime absorbed of its weight in gases of No. 4 furnace. 1-72per cent. COP. ? I. LOWTHIAN BELL ON THE which this gas was at any particular point generated by the whole mass of ore it would be imposaible to discover how much of it so formed was taken up by the lime only to be again expelled in the lower and hotter portions of the furnace. It is almost needless to say that when lime or its carbonate exists in the ores naturally the same consequences will happen more or less as those described in the case of the earth used separately and constituting the flux. To afford a clearer idea than figures can do of the want of uniformity in composition of the gases from different depths of firnaces a8 determined by analysis I have constructed a few diapams drawn to a scale in which carbonic acid is shown by the darker shaded part and carbonic oxide by the lighter.In the four diagrams the scale ia according to volumetric analysis and the authorities quoted. Locality Veckerhagen. Authority Bun s en. Temperature blast 278" C. (532 F.) Fuel Charcoal. 5 c -I---TopofFurnace 5 --Pr. Cent. Pr. Cent. ft. in. CO2. co. Locality Baerum. Authority Scheerer and Lan gberg. Temperature blast 200*C. (392 F.) Fuel Charcoal. Top. -.,---_ ---* c02. co. -Limits of quantity of co. ft. in. -Bottom 32 1 CHEMISTRY OF THE BLAST-FURNACE.221 Locality SQraing. Authority Ebelmen. Temperature bla& 100' C. (212O F.) Fuel Coke. Locality Alfieton. Authority Bunsen and Playfair. Tempera+ ture blast 330' C. (625 F.) Fuel raw Coal. Topi Depth fi.omtop 6 ......... 8 ......... 11 ......... 14 ......... 17 ......... 20 ......... 23 ......... 2p ......... ......... 87-43 The difficulty which attends obtaining an average sample of the gases below the level of the top of the furnace does not present itaelf when the object is to procure specimens of the gases after they have left the furnace. The following portions of gas from No. 4 Clarence furnace s2 828 I. LOWTHIAN BELL ON THE 48 feet high,were carefully taken and analyzed many in my presence by Mr.W. Moody the chief assistant in the Washing- ton laboratory. The results when the trials were repeated are given so that some opinion may be formed of the attention bestowed on the experiments. coa. co. Volumes of in 100 I Volumes*" 1st Trial. 2nd Trial. 1st Trial. 2nd Trial. 1st Trial. 2nd Trial. Hour sample taken. 1 p.m. 6-25 26*30 67-45 1.56 6*24 6 -70 34-70 59-06 2.15 6-94 6 '73 34.40 35-40 58-66 67-87 3.0 5 -30 5.75 35 *so 35-64 58.90 58.61 3.15 4-75 5 -12 31 -00 30.25 64.25 64.63 3. 55 31 -12 62-97 1 4.20 29*72 28.90 64.46 65.10 A very brief examination of the figures contained in the above table proves how liable to variation is the nature of the changes going on in a blast-furnace eveu when to all appearance the materials employed are precisely the same.If the gases of a blast-furnace have to furnish us with any data from which we may endeavour to draw just conclusions of the nature of the chemical action going on in its interior it appears to me that little reliance can be placed on any analyses excepting of those of the gases as they escape. If as I think most probable little if indeed any carbonic acid leaves the lime until it reaches a portion of the furnace when the heat is such as to resolve the liberated acid into car- J(r The following figures show the above volumetric constituents converted into weights :-cop co. N by Difference Hour. 1st Trial 2ad Trial. 1st Trial. 2nd Trial. lat Trial. 2nd Trial.1 p.m. 9'60 Nil 25-86 Kil 64.54 Nil 1.55 9.55 Lost 33-90 Lost 56.55 Lost 2.15 10.78 10.26 34.10 34.51 55-12 55-23 3.0 8.13 8.83 35.10 34.93 66-77' 56.24 3.1 5 7-86 7'33 29.78 30.59 62.36 62.08 3.55 9'06 Lost 30.50 Lost 60.44 Lost 4.20 8.98 9-22 28'68 28-30 62.34 62.48 CHEMISTRY OF THE BLAST-FURNACE. bonk oxide it is clear that all the carbonic acid found in the gases must be due to the deoxidation of the ore which ac- cording to the views laid down in this paper is effected at a lower temperature than was supposed by Tunner and at one where carbonic acid is not decomposed by incandescent carbon. The ironstone may be in such large masses like those on the table that the whole of the oxygen may not be expelled until a considerable depth in the funace is reached and then of course the carbonic acid generated by the process of reduction may experience the same $ate aa that liberated from the car- bonate of lime.It is not a diflicult matter to oalculate what the composition of fimnace gases ought to be supposing a certain quantity of coke and limestone to be consumed to the ton of iron and the 8010 source of carbonic acid to be the ore by its deoxidation. Assume the coke used to be 23.20 cwts. and the limestone 11.60 cwts per tou of pig iron containing 19 cwts. of pure iron. The coke may be taken as consisting of-Pure carbon.. ............ 21-80 Ash .................... -1.40 23.20 And the limestone will oonsist of-Lime ....................................6.50 Carbon 1.39 5.10 Oxygen 3.71 to form carbonic acid -11.60 The ironstone will consist of iron 19 cwts 8-14 ,, Earths.. ........ 22.86 , 50.00 The total carbon then to be dealt with is-In the coke ................ 21.80 In the limestone ............ 1-39 -23.19 cwts. From which must be deducted the arbon to combine with the iron . *74 99 -.-Leaving to go off as carbonic acid and as carbonic oxide ................ 26.45 ,) I. LOWTHTAN BELL ON THE The total quantity of oxygen we have in the minerals ap-plicable to oxidizing carbon is in the-Ore. ............ 8.14 Limestone. ....... 3.71 -11-85 To which may be added from the decomposition of water contained in the blast ....................085 Cwts.. ....... 12.70 C&. To convert 22.45 cwts. carbon to the state of carbonic oxide will require of oxygen .................. 29.93 But as applicable to this we have in the limestone 3.71 and in the blast 085.. .................... 4-56 Leaving to be derived from the atmosphere ...... 25-37 25.37 atmospheric oxygen is equal to nitrogen .... 84.93 8.14 oxygen in the ore will give of carbonic acid generated by its action on carbonic oxide . . . 22.38 22-38 carbonic acid contain$ 6.10 of carbon leaving 16.35 (22.45 -6.10) carbon to give of carbonic oxide ...................................... 38.15 Total weight of gases per ton of iron .. 145.46 Supposing then the carbonic acid fiom the limestone to be decomposed and that generated by the reduction of the ore to escape as such the proportions in which nitrogen carbonic acid and carbonic oxide ahould be found in the escaping gases would be-Nitrogen ................58.38 Carbonic acid ............ 15-39 Carbonic oxide ............ 26-23 100*00 The analyses of the gases fiom a blast-furnace making forge iron with precisely the quantity of materials named in the above calculatian gave the following results by weight :- CHEMISTRY OF THE BLAST-FURNACE. I cop co. N 1 y Difference. I 1 Taken at 1st Trial. 2nd Trial. 1st Trial. 2nd Trial 1st Tri \1. 2nd Trial. --1 -I --Hour. 1p.m.2.10 18 -28 14.60 18 -20 15.10 27-19 30-09 27 '19 28 *60 54*53 55 -31 54 -61 56 -30 2.40 15.05 15-58 18.61 1950 66*34 64 -92 3.30 18:50 Lost 25* 80 rAost 55'70 Lost 3.45 4.0 165.86 16 -12 16 %l 25 $0 23 '00 24 %8 58 *65 60*88 58 'il 4.10 19.71 19*71 23 '60 23*60 56.69 56 -69 4.50 19-25 19.14 27 48 27*I0 53*67 53 -76 Average . . 17 *17 25.11 57 -72 These figures show a close appraximation to the theoreticd calculation there being rather more carbonic acid as shown by the analyses than the previous estbate would indicate &om which it may be inferred that not only the whole of the iron- stone was reduced in the upper and cooler part of the furndce but also that a portion of the carbonic acid which was contained in the limestone was also expelled before the flux reached a part of the fhrnace where the heat was intense enough to de-compose it,* On watching the slag from a furnace in the Cleveland district as it falls from a spout into the vessel for receiving it a white fume is perceived.A portion of this may be sulphurous acid Gombining with hygrometric water but by far the greater quantity consists of the earths themselves in the state of vapour at least such I conceive to be the case. This vaporized lime alumina magnesia and silica ascend through the contents of the furnace and are no doubt to a considerable extent condensed * This is consistent with observation for in an experiment mentioned in a discus- sion before the Institution of Mechanical Engineers 28th January last I showed that coke was incapable of decomposing carbonic acid at a temperature which completely melted German green glass.Upon the same occasion I gave it as my impression that one of the advantages in using high furnaces was hat they did not permit the gases to escape at a temperature at which they were still capable of deoxidizing the ores. This latter circumstance was also alluded to by the President Dr. Williamson in the discussion which followed the reading of this paper. The analj ses just quoted were of gases taken from a furnace 80 feet high and containing about 11,500 cubic feet so that as far as chemical action is concerned its dimensions appear to be Sufi-cient. I. LOWTHIAN BELL ON THE as a sublimate on the way but eventually a certain quantity escapes fiom the top constituting the mass of fume visible in most smelting districts but particularly conspicuous on the banks of the Tees.At one time I supposed. this volatilizing sufficient to account for a difficulty in reconciling the composition of our slags with the earthy materials which really entered the furnace. This discrepancy I have since ascertained is due to the great variations in the composition of our ironstone itself. As might be expected the higher the furnace in which the smelting is being carried on the greater is the interception of these vapourized earths and the other substances associated with them but the actual quantity varies in the same furnace at different times. From a furnace 48 feet high the quantity amounted upon one occasion to 59.09 lbs.per ton of iron made and at another to 77.31 lbs. while in an 80 feet furnace the weight for the same quantity of metal was 27.24 and 19.54 lbs. respectively upon the two days when the experiment was made.* To this short account of the gases I would only add that instead of escaping into the atmosphere and burning at the tops of the firnaces as formerly happened and still happens generally in Staffordshire and uniformly so in Scotland the carbonic oxide they contain is burnt for raising steam for the blast engines and for heating the air by which something like * The estimated weight of slag per ton of iron is about 30 cwts. The following shows the composition of this condensed fume taken out of the gas. pipes :-Silica and sand ............................44-82 Alumina.. ................................ 16-00 Lime.. ................................... 12.15 Magneda.. ................................ -67 Peroxide of iron ........................... 8'20 Oxide of zinc.. ............................ 4.60 Sulphuric acid.. ........................... 8.80 Potash.................................... -40 Sods.. .................................... 6-85 Chlorine .................................. 1.66 Water.. .................................. 6.60 99.65 Report I. L. Bell to British Association 1863 A second PJample waa coIlected by drawing through water for some hours the gases CHEMISTRY OF THE BLAST-FURNACE. a saving of 600,000 tons of coal per annum is effected in those works smelting the ironstone of North Yorkshire.Having now traced the progress of the solid materials down through the furnace and considered the action of the gaseous current flowing upwards among them let us devote a few minutes to an examination of the blast by means of which we obtain heat &om the fuel to fuse the iron and slag and generate carbonic oxide to effect the reduction and carburization of the metal which is the object of the process. The effect of cold on our atmosphere being to deprive it of a considerable portion of its moisture and to contract its bulk a cubic foot of air in winter contains of course less watery vapour and more oxygen than is embraced within the same space in summer. It is obvious that there is no necessary connection between a rise in temperature and the presence of aqueous vapour and a diminution of the supply of o$ygen but in.the absence of correct and sufficient information on the mbject 40 years ago ironsmelters ascribed some virtue to a blast as cold as circum- stances permitted because in the winter season as a rule they made more iron with less fuel than in summer simply because fromone of our furnaces so as to secure the presence of the whole of the solid constituents before analysing. It contained- Soluble in water- Loss in heating ............................ 10.46 Silica.. ................................... 1.37 Alumina.. ................................ 12.20 Lime. ....................................Tr. Magnesia.. ................................ Tr. Chlorine .................................. $7 Sulphuric acid.. ............................ 59 Oxide of zinc.. ............................ 4.58 Carbonates of soda and potash.. .............. 22.90 52.67 Insonble in water-Silica. .................................... 11.00 Alumina and oxide of iron,. ................. 103’6 Lime ..................................... 2-06 Magnesia.. ................................ Tr. Oxide of zinc,. ............................ 13.28 Carbonic acid,. ............................ 7.00 Alkaline mlts.. ............................ 3.07 -4P17 -99.84 234 I. LOWTHIAN BELL ON THE each stroke of their blast engine supplied them with more oxygen and less carbon was absorbed in the decomposition of watery vapour than in summer.Under these circumstances it is not surprising that Neils on's proposition to heat the blast before it entered the furnace was not favourably received or that a considerable time elapsed before the value of his invention was recognized by practical men. It is not my intention to detain you with any comparison between the nature of hot and cold blast iron indeed this would be a task beyond my power for want of the necessary data. There is no doubt that some of the best if not the best makes of iron in this country are produced by means of cold blast; but whether this excellence of quality is due to the temperature of the air or to the materials employed is a point upon which no opinion of any value can be formed until the same materials have been treated by both systems and the results experimentally and practically examined.The fwt however that out of the four or five millions of tons of pig-iron annually produced in this empire all but one or two hundred thousand tons are smelted by means of heated air will be accepted as a proof of the soundness of Neilson's dis-covery. The chief recommendation of the hot blast is the economy of fuel obtained by means of its use and it is this attribute which possesses interest to ourselves as chemists furnishing as it does a field of inquiry into the nature of the combustion and the appropriation of the heat in the blast-furnace. In entering upon an explanation of the action of the hot blast we must consent to lay aside those accounts which inform us that immediately after its introduction the mere heating of the air up to 320" F.(161 C.) enabled a smelter to reduce the consumption of coal for one toil of iron from 7+tons to 2+ tons. If it can be shown that -the progress of smelting-acience has been such a8 to reduce the consumption of coke in a furnace blown with cold air until it is within 10 or 11 cwts. per ton of iron of that used in a furnace supplied with air heated not to 320 F. (160' C.) but to 650' E' (339' C.) this is the saving we are called upon to explain and not five or six tons of coal how- ever instrumental the employment of hot blast may have been CHEMISTRY OF THE BLAST-FURNACE.235 in leading up to those general improvements which have bene fited both modes of operating. With the view of satisfying myself by personal enquiry what the consumption of fuel in furnaces fed with cold blast actually is and for obtaining information on the process generally I have recently visited the establishments of the Lilleshall Iron Company in Shropshire of the Blenavon Iron Company and that of my send Mr. Crawshay in South Wales and I cannot deny myself the pleasure of recording in this paper my gratefill thanks for the unreserved access which was granted for t.he purpose of making the necessary experiments and observatians. Granting then for the present moment that a furnace having its blast heated to 650" F.(339OC.) can make a ton of iron for 10 or 11 cwt. less coke than one driven with cold air this extent of saving moderate as it is when compared to the five tons of former days requires some explanation wheu it is remembered that the blast has the 650°F. (339' C.) of heat communicated to it by means of 5 cwt. of coal of which I have ascertained that more than one half is wasted in the hot air apparatus," so that practically you have the heat of about 2 cwt. of fuel burnt outside the blast furnace effecting a saving of that burnt in its interior of 10 cwt. to 11cwt. The generally received opinion respecting the mode iu which hot air effects the reduction in the cansumption of coke is that a higher temperature is commanded in the furnace by its use than when cold air is employed and as Dr.Percy truly says in his recent work on metallurgy 4'suppose a cer-+ tain metal to require l,OOOo C. for its fusion it might be subjected to 999' for ever without melting. Just so," he continues may be in the blast-furnace with respect to the carburization of the reduced iron and certain other chemical actions which moreover take place with slowness at one temperature and with rapidity at another more elevated. In order to produce these actions in a furnace on cold blast it is requisite to consume a much larger quantity of coal than in a furnace on hot blast. A few degrees of temperature may make all the difference." The Doctor goes on to explain cer- * The temperature of the gases of combustion leaving the hot-air stovesat the Clarence Works watj found to be about 1400" F.(760 C.) to which haa to be added loss from radiation 236 r.LOWTHIAN BELL ON THE minor causes which may give rise to some saving but in the end he admits that none of the answers which have been given as explanations of the theory of the hot blast are to himself satisfactory and that a solution of the question is still wanting. Not as explanatory but as a statement of a probable fact Dr. P er c y reminds us that inasmuch as for every ton of iron made a larger quantity of coke is consumed when the furnace is driven with cold than with hot air it is clear the number of units of heat evolved can hare little to do with the matter and that this being admitted the inevitable con-clusion is that caZoriJic intensity must be concerned and that the temperature of what may be designated as the most active part of the furnace must be higher with the hot blast than with the cold.It is needless to trouble you with quotations from other authorities who all appear to agree with this writer although Borne of them quote other reason8 than those assigned by him in support of the view just stated. Let us consider how far this idea of increased calorific in- tensity accords with probability and with fact and for this purpose it may be well to regard the subject in the first instance from the practical point of view. It will probably be conceded that if the temperature of me furnace were greater than that of another the fused materials from it i.e.pig-iron and slag should show some symptoms of the difference of temperature. Most of the cold blast iron smelters with whom I have discussed the subject during recent enquiries and all of whom have also furnaces blown with heated air appear to consider that the iron from the latter is the more fluid of the two. This however may be due to some difFerence in composition of the metal itself; for they all at the same time admitted that so far as heat could be estimated by colour there existed no reason for supposing the temperature of either slag or iron to be lower from a furnace driven by cold than from one slipplied with hot blast. In com- pany with our own furnace manager Mr. Thompson a gentleman of large experience who assisted me in my observa-tions I certainly arrived at the same conclusion.Again experience and practice have demomtrated beyond all question that the production of different qualities of pig iron is determined by the temperature of the furnace-No. 1 CHEMISTRY OF TElE BLAST-FURNACE. bcing obtained when the working is at the hottest; indeed so established a fact is this that smelters are pretty well agreed among themselves as to the additional weight of coke which is required to raise their produce each number in the scale. Now this being the case where,it may be asked is the authority for supposing that the heat of a hot blast-furnace running say No. 3 iron is higher than that of a cold blast-furnace producing the same quality? Were the ''calorific intensity " greater as Dr.Percy supposes one would imagine from the law just al- luded to a higher quality of metal would be the result as indeed happens whenever from any cause the lieat is in- creased. It is very true that Then a furnace is looked into at the tuyeres one blown with hot-blast exhibits a dazzling white heat whereas the large amount of cool air poured into a cold-blast furnace produces a tuyere which is inore or less black; but are we entitled to consider this refrigeration more than local? At no portion of the furnace except at the top does there exist less reason why the composition of the gases should experience more variation than near the region of fusion ;for by this time all chemical change in the ore and flux has been ac- complished.Neither is there any portion with the exception above given where an average sample is more easily collected inasmuch as the sectional area of the furnace is much smaller and its condition generally more uniform than higher up. Now the first effect upon the blast onits being admittedinto the furnace is the conversion of its oxygen into carbonic acid and the extent of space in which this change is effected may be accepted as an expression of the intensity of the heat produced in that space. On looking over the analyses of the gases of fwnaces I cannot find any justificat.ion for the idea that the oxygen unites more rapidly with carbon in hot than in cold- blast furnaces. The same mode of showing the meaning which is intended to be conveyed has been pursued as when describing the com- position of the gases cf the furnace viz.by diagram. The first one shows the carbonic acid and carbonic oxide in a cold blast and the other in a hot-blast furnace with air heated to 190° C. (374" F.) both at Clerval in France using charcoal the analyses being those of Ebelrnen. 238 I. LoWTHIAH mL ON TtlE Top. Corn BLAST,Fig. I. bP HOT BLAST Fig. IT. In the diagram No. 1 cold bla.st the carbon vapour from existing entirely as carbonic acid at the tuyeres by the time it travels 22 inches exists only in this form to the extent of -93 per cent. of the total gases and by the time 5 feet from the bottom is reached there is no longer any carbonic acid present.In other words the oxygen of the blast has in this space been all con-verted into carbonic acid and afterwards changed into carbonic oxide. In the case of the hot-blast furnace a distance of 3 feet fkom the bottom shows 0.31 per cent. of carbonic acid and a height of 93 feet has to be travelled before it disappears; 60 that uu-doubtedly 60 far as temperature can be judged of by the small-ness of the space in which perfect oxidation and subsequent rednction to carbouic oxide is effected the cold-blast furnace would appear to be the hotter of the two. Certainly the dia- 2HEMISTRY OF THE BLAST-FURXACE. 239 grams in which the dative dimensions of these spacers are expressed by the dark shading in each case comprised within a,b C do not exhibit any reason for supposing the temperature of the zone of fusion is higher with the hot blast than that of cold; whereas some pounds have been given to show that the difference if any is very trifling.Permit me to invite your attention with a view of endeavour- ing to ascertain whether the mode of action of the hot-blast cannot be explained upon different grounds. Before doing so it may be questioned whether the supposed calorific intensity suggested by Dr. Percy as being required fGr the carburization of the reduced iron and some at least of the other chemical actions rnay not be omitted in the enquiry ; for if the views laid down in this paper are correct most of the chemical changes on the materials have been effected in a much cooler part of the furnace.It will be recollected that we started upon this enquiry with supposing that the heat from 2 cwt. or thereabouts of fuel which we will for simplicity's sake assume to be pure carbon represents the heat thrown into a furnace by means of the blast being heated to 339' C. (650" F.). In practice we are pretty near the truth in accepting as a fact that an estimate of the heat developed by the blast on the coke is obtained by con- sidering its oxygen coiiverted into carbonic oxide ; for although at the instant of its admission carbonic acid is generated this substance is almost as rapidly converted into carbonic oxide by the action of the incandescent coke. But in the hot-air stoves the 2 cwt. of carbon is converted permanently into its highest state of oxidation and taking the units of heat as 2221' C for burning carbon to carbonic o&de and as 7900" C.for burning carbon to carbonic acid the 2 cwt. burnt in the stove will repre-sent 7.11 cwt. of carbon burnt in the furnace or say some- thing like 7+ cmt. of coke. In round numbers therefore wemay consider 7& cwt. of our saving of the 10 or 11cwts. to be accounted for leaving still 2+ to 34 cwts. for further investigation. Now let us assume that the coke required is 40 cwt. for the ton of cold-blast iron and into the fiirnace blast heated to 339O (650' F.) is suddenly introduced which is as we have seen equal in calorific power to 76 cwt. of coke so that 80 far as a mere question of heat is concerned something like 474 cwt.of 240 I. LQWTHIAN BELL ON THE coke iB being applied to the production of a ton of metal for which 40cwt. mill suffice. A common yield of calcined clay ironstone is 40 per cent. so that 50 cwt. are required for a ton to which has to be added say 12 cwt. of limestone. The ‘‘burden,” then for one ton of cold-blast iron would be-Coke 40 cwt. ; calcined ironstone 50 cwt. ; limestone 12 cwt. But by the addition of the equivalent of 74 cwt. of coke these proportions will requhe a corresponding modification and a ton of iron will be represented by-heat in blast equal to 7Q cwt. of coke ; coke reduced by this addition of heat in the blast to 32t cwh. ; calcined ironstone and limestone as before viz. 62 together.But what is the effect on the fuimace itself by such a change in the proportion of its contents. To answer this let us imagine a furnace with a capacity of 6,000 cubic feet. The weights of the materials used at the Clarence Works have been carefully ascertained and as charged into the fur-nace are- Coke -234 cwt. per cubic foot as contained in the barrow. Calcined iron-stone -624 cwt. per cubic foot as contained in the barrow. Limestone -706 cwt. per cubic foot as contained in the barrow or taking the average of the two last together in the propor- tions they are used -640 cwt. will represent a cubic foot. It was further determined that the weight of material in a fwnace before being lighted was such as to indicate a compres- sion of something like 25 per cwt.so that a furnace of 6,000 cubic feet would contain 7,500cubic feet of materials as measured in the clmrging barrows. By these figures it would appear that such a furnace work- ing on cold-blast would contain- Coke .,,... . . . . .....-.......... 56 tons Calcined ironstone and limestone . . -87 , 143 9 but introduce the air heated so as to reduce the coke to about 30 cwt. to the ton’of iron and the furnace would contain of CHEMISTRY OF THE BLAST-FURNACE. Coke . . . . . . . . . . . . . . . . . . 50 tons B... Calcined ironstone and lime . . . . 103 ,) -153 ,> Neither of these two sets of figures really represents what is contained in a blast furnace at any one time when filled and in working order.In the case of the hot-blast furnace 103 tons of ironstone and limestone represents 24 hours' working whereas as is well known it requires something like 36 hours at the usual rate of driving to pass the entire contents through such a furnace. The estimate is based on what 7,500 cubic feet will contain of cold materials whereas when the furnace is in fill1 operation the coke loses considerably in weight before it reaches the tuyeres and the other materials become greatly condensed as they approach the seat of fusion. It would be almost impossible to ascertain to what extent these figures become modified by the action of trhe heat when the furnace is in blast or what the effect of the altered propor- tions would be on the temperature of the ascending gases.To obtain the exact figures for this we ought to have the specific heat of all the various materials in the furnace; and it would be equally difficult to ascertain what the specific heat6 of the contents of the furnace really are during the process of smelting as it is difficult to ascertain the temperature of the different portions of the interior of a furnace. S chinz has shown in a recent work how rapidly the specific heats increase with iise of temperature. According to his researches the following list shows the change of specific heat with elevation of temperature :-At Coke. Limestone. Lime. Iron ore Iron. 81%. 100" C. -157 -166 -216 -171 250" C. '186 *273 -233 -185 500" C. -234 -451 ,260 -209 750" C. '253 '628 '287 0233 1000" C.-330 -314 -257 ,152 -259 1500"C. -428 -184 '822 2000" C. ,525 *216 -384 Without any information to guide ua as to the exact con- dition chemically speaking of the contents of the furnace or the rate at which they lose weight and acquire heat it would be VOL. XXIII. T I. LOWTIEAN BELL ON THE mere guws-work to eBtimate the number of units of heat inter- cepted by the materials under treatment. That the withdrawal of so many cubic feet of coke and the substitution of substances nearly three times its weight and with a mean specifm heat rather higher than that of the coke itself mud permit a more perfect absorption of heat froin the ascending current of gas ia obvious. In illustration of this an experiment made at the Clarence works of this may be quoted.Through a pipe 12 inches in diameter and 6 feet high a given volume of air heated to the melting point of lead was passed. The pipe was filled with coke properly dried and afterward8 with calcined ironstone and then limestone. The power of intercepting heat from the same volume of air is expressed by the following numbers :-For Coke. ................. 100 , Calcined ironstone ...... 188 99 Limestone ............ 144 Looking at the complicated nature of the problem it appears as if there is no alternative left but to ascertain the actual amount of heat carried off in the escaping gases after they have performed their work in the furnace and this during a whole day was done most carefully at the Cyfarthfa works at a hot-and cold- blast furnace.The mode of procedure was as follows:-To ascertain the temperature of the gases a pyrometer made by Kraus of Paris was plunged into the gases where they left the the furnace and occasionally an observation was taken by means of ap-paratus supplied by Mr. C. W. Siemens consisting of a copper cylinder which being immersed in the gases indicated their temperature by the amount of heat it conferred on a given quantity of water. Both of these instruments are open to the objection of requiring t-ime so that in cases where the tempera- ture is constantly changing neither gives results which are strictly correct. To obviate this difficulty I constructed an0 ther pyrometer which though liable to some irregularity possesses the advantage of being much more immediate in its indications.It wag simply a copper tube,about 3feet longand 1inch diameter closed at the lower end and screwed into aBourdon’s pressure guage so that it was hermetically tight. The expansion of the CHEMlSTBP OF THE BLAST-FURNACE. air by increasing the presmm enabled me to read off minute variations almost the instant they took place. To estimate with strict correctness the heat carried off with the gases an analysis of samples extending over some hours would have been required both for the purpose of calculating the quantity and the specific heat. This was not in my power to do and in consequence the composition of the escaping gases has been assumed as being the same as those given off by a furnace of nearly the same dimensions at the Clarence works.It is believed that any difference in respect to tb Will not seriously affect the results of the calculation. The gases were assumed to contain according to weight- CO 9 CO 32 N 59 = 100 The C in CO = 2.45 C in CO = 13.71 = total C 16-16 0 , = 6.550 , = 18.29 , 0 24.84 Total CO 9.00 total CO 32 total C & 0 41.00 Coke used per ton of iron was cmts. 34.80 Deduct ash 5 per cent. 1.74 HO (weather was wet) 5 , 1.74 For combination with iron *74 -4-22 3098 Caxbon in limestone ........................ 2-13 -Total carbon going off in gases .............. 32-70 With the composition of the gase8 given above this cahon will be volatilized in the following state m-c0 496 cwts.co 27.74 ,9 I-32.70 C 4.96 for conversion to CO reqwers 013.23 C 27.74 co 036.99 9) 9? 32-10 Total 0 50.2 2 l3uk in %hernskeials themselves there is-0 in the CO of the limestone (viz. 17.66 cwta per ton iron) = . .I 5.65 cwb. 0 in 48-43 ores (part of Fe being aa FeO) .......................... 7-35 ,, -13.00 -Leaving to be supplied by blast of 0 ...... 37.22 I. LOWTHIAN BELL ON THE The total weight then of the gases would be- Carbon.. ............................ 32.70 cwts Oxygen ........................... 50.22 .. Nitrogen accompanying 37*220 of blast 124.60 ,) Water in coke 1.74 water in ore 2.19 .. 3.93 211.45 We have as total weight of gases-C 496 + 0 13-23 = CO 18.19 cwts.C 27-74 + 0 36.99 = CO 64.73 ,, N 124.60 , 330 3.93 )) -= 211.45 ) The mean temperature of these gases as they left the fuimace was ascertained to be 445' C. (833 F.) By multiplying these weights by their various specific heats and temperature we have- C02 18.19 x 0212 x 445' CO 64-73 x -288 x 445' N 124.60 K -275 x 445' = 26967 I HO 3-93 x 1.0 x 445' And this divided by 2221 units of heat burning C to CO gives-12.16 cwt carbon or say 12-76dry coke as going off with the escaping @sea from the cold-blast furnace. In the erne of the hot-blnst furnace with air heated to 320' C. (608 F,),the calculations stand thu8- Coke used per ton of iron was 26.74 cwts. Deduct ash in coke 5 per cent. 1.33 Ditto HO in do.9 1.33 Ditto C combined with iron *74 340 f9 -23-34 ) Lime was added in its caustic state hence there is no carbon to include fiom this source. Upon the same bask as the previous calculation the carbon will be given off in the gases a8- co,. ........... 3.53 cwts. CO ............ 19-81 .. 23.34 CHEMISTRY 0%' THE BLAST-FURNACE. C 3.53 requires for conversion to CO -of 0 9-41 -17 c 19-81 CO -of 0 26.41 c- 23.34 35.82 Less 0 in the ores Fe partly existing as FeO 8-12 Leaving 0 to be supplied by blast . . ,. . . . . 27.70 Total weight of gases will be- Carbon . . . . . . . . . . . . . . . . . . .. . . 23-34 Oxygen.. .. . . . . . . . . . . . . . . . . 35-82 Nitrogen accompanying 27.70 0 92.73 Water in coke 1-33 and ore 1-73 3.06 154.95 cwts.The mean temperature of these gases was ascertained to be 477" C. (891 I?.) and their estimated constitution would be ap1 follows :-C 3-53 + 0 9.41 = CO 12.94 C 19.81 + 0 26-41 = CO 46.22 N 92-73 HO 3.06 154.95 cwts. By multiplying these weights by temperature and specific heats we have- C02 12.94 x -2127 HO 3.06 x l*OOJ This divided by 2221 = 9.57 cwts. carbon or dry coke 10-06. Now as the heat escaping from the cold blast hrnace repre- slented in coke for each ton of iron . . . . . . . . . . . . 12.76 cwts. Whereas with that on hot blast it is only.. . . . . . . 10.04 -It follows there is eacaping fiom the cold blast * The fact that very different materials were employed in the two furnaces which were examined prevents a strict comparison between their respective temperaturea being instituted.All that can be done is to ascertain in both wes the actual amount of heat escaping. %46 I. LOWTEIAN BELL ON THE f!urnace above that going off from the hot heat equal to coke.. ............................ 2.72 cwts. 7 We havein consequence the total saving of coke as fallows :-1st. By use of blarst heated as formerly stated 7.50 cwts. 2nd. By diminution of loss of heat in the escaping gases .................... 2-72 ,, -10.22 ) Which accords with the saving given as effected by the use of 5 cwts. of coal for heating the air of which only about 2 cwts. were really available. It may be interesting to compare the duty of the two dif-ferent furnaces by deducting the heat carried off by the waste gwe8 and that required for melting the slag which latter vmies of course in amount accordingto the minerals used.In estimating the fuel required for this latter object Vathaire's figures of 550 units per kilogramme of slag ist accepted as the basis of calculation. The hot-blast furnace in Wales stands thus making white iron-Coke used per ton of iron.. ............ 26.74 cwts. Heat contained in 120 cwta. of blast at 320' 120 x *287 x 320 -= carbon 4.95 = coke 516 2221 -31*w9) Heat escaping with gases- As formerly cahlated = carbon 9.57 Melting 23 cwt. slag do. ...... 5.70 -15.27 = coke 16.04 cwh. Leaving for reduction and fusion of metal loss -&om rdbtbn &c......................... 15.86 n The cdd-blast furnace in Wales exhit@ the foIlawhg results also praducing white iron :-Coke used per tan of iron ae formerly given 34.80 Go Heat 37" C. (100' F.) contained in blast pro-duced br compemioxb i31 blwt engine 162 x -287 x 87 + 2221.. .............. y78 __.I.._ 3*68 % CHEMISTRY OF THE BLAST-mNACE Heat escaping with gaseB as formerly estimated = carbon ................ 12.16 Melting 30 cwt. of slag do. 7043 19.59 = coke 20.49 Leaving for reduction and fusion of metal -loss from radiation &c. ................ 15.09" Let us test by another method this mode of calculation. Suppose two furnaces of such dimensions and using such a kind of mineral that for producing the same quality of iron the consumption was 30 cwt.per ton of iron for hot Ha& and 40 cwt. for cold blast. For the hot blabt furnace we have coke.. .. 30 cwts. And with the air at 800 F. (426 C.) there will be heat equal in coke to about.. .... -8 , 38 9) Deduct for heat carried off by gases some- thing like.. ......................... 9 , Leaving for reducing iron fusing it and the slag loss by radiation &c. ............ 29 .. -In the case of the cold blast haces the coke is taken at ...................... 40 .. Added with blast by compression heat equal in coke to about.. .................. -1 .. 41 9t Carried off by gases say ................ 12 .. I Leaving for reduction of iron &c......... 29 .. 0 Imagine now that instead of introducing with the blast the heat of 8 cwts. of coke an equivalent of which and more escapes at the top of a low furnace measures were taken to prevent this 8ource of loss which is something like 12 cwt. of coke in the caBe of one blown with cold air. This could be done by adding something to the height and thus cause the highly heated gases to yield up the greater portion of their heat to the additional =aterials contained in this increase of size. If the temperature of f The iron from this furnace was somewhat inferior in quality to that from the I. LOWTHIAN BELL ON THE CHIXMISTRY ETC. the gasea from a cold blast furnace a.as such that it represented 2 instead of 12 cwts. of coke a clear saving of 10 cwts.would be effected by the change or the 40 cwts. of coke per ton of iron might be reduced to 30 cwts. for we wonld have 30 + 1cwt. for heat conveyed in The blast = ...................... 31 Less carried off in gases ........... -2 Leaving . 29 for actual furnace work. NOW,this is exactly what has been done at the Lilleshall Iron Works. Furnaces formerly 50 feet high have been raised to 71 feet in height and the consequence has been that those of the latter dimensions blown with cold air are making iron for the same quantity of fuel used by hot blast furnaces of the former size viz. 50 feet. Unfortunately the mode of construction is not such as to permit a verification of the actual heat going away from each; but there is little doubt that were this done we should see that the Bum of heat introduced by coke and blast minus that escaping gives in both cases the same result to -represent work actually performed.Of course all this forms no argument against the economy of the hot blast ; because from furnaces of 48 and 50 feet blown with heated air something like 10 cwt. of coke escapes in the gases-a loss which has been reduced to something under one half of this by adding 30 feet to their height; indeed it was with hot-blast furnaces that the great advantage of increased height was first demonstrated. It is almost needless to say that there are in connection with the blast-furnace many other questions of a highly inter- esting nature in a scientific point of view as well as most im- portant regarded as matters of practical economy which the length of time I have occupied your attention forbids me to enter upon.Such are the actual heat given off by the combustion of the fuel compared with the real effect produced together with many others. I have instead of going into these preferred submitting for your consideration views connected with the subject of iron smelting which so far as 1 know differ in some respects from those previously expressed. I. LOWTHIAN BELL ON TIEE C€IEMISTRY ETC. 249 The President in inviting discussion said :There is scarcely any branch of manufacture which requires so many various qualities of a rare aiid high kind as this particular one in which Nr.13 ell is pre-eminent and certainly among ironmasters there is none equal to himself in the combination of those vaiioiis qualities. His scientific skill and industrial vigour have led to the construction of iron furnaces which are unsur- passed in the perfection of the operations which pertain to them The subject is one so complicated that Mr. Bell’s views will be considered exceedingly valuable in relation to it and certainly all will feel interested in having so full and so masterly an exposition from himself in this matter. Mr. Siemens With regard to the saving effected by hot blast a great deal of controversy has taken place and I am very glad to see that Mr. Bell has realJy tackled the question by reducing it to figures. At first sight it appears strange that the combustion of 2 cwts.of carbon added to the blast should save 10 cwts. of coal in the blast-furnace ; but a little consideration would I think bring us already to this conclusion. If the result of combustion were carbonic acid only then every 6 Ibs. of carbon added in the shape of heat to the blast would necessaiily save 14 lbs. in the furnace that being the propor- tion of heat developed in burning carbon into carbonic oxide and into carbonic acid; but we find the result of combustion is not carbonic oxide but a mixture of carbonic oxide and carbonic acid. It may be assumed to be in a furnace worked with hot blast one-fifth carbonic acid and four-fifths carbonic oxide ; and if we take these proportions we shall find that the effect of 1 Ib.of combustion outside the furnace wdd probably produce a saving of 4 Ibs. inside the furnace. But why is the saving greater? If we suppose t-hat a mixture of air reduced ore and carbon comes down the fumace and is met by the blast the first action is complete conihustion into carbonic acid; but almost simultaneously with that action the reducing action or the absorbing action of the carbonic acid upon carbon takes place also. The carbonic acid is reduced to carbonic oxide and this reduction is accompanied by a great refrigera- ting effect. If cold blast is used there must be a larger proportion of carbon present with the ore and there must be a larger surface of carbon at once exposed to the carbonic acid formed in order to effect its reduction.It has been determined VOL. XXII. U 250 I. LOWTRIAN BELL ON THE practically that a cold-blast furnace not only works hotter at the top but that the proportion of carbonic acid is greater in the cage of a hot than of a cold-blast furnace; it would therefore follow that the hot blast has not only produced a higher temperature at the bottom but reduced a mixture of carbonic oxide and carbonic acid giving a larger margin of heat developed or less refrigerating action introduced by the forma- tion of carhonic oxide. Perhaps Mr. Bell will be kind enough to tell us whether on raising the temperature of the blast the proportion of carbonic acid gas at the top of the furnace is not increased. Mr. Bell If you had a hot and cold-blast finmace working together irrespective of the results with the same quantity of fiiel and the same quantity of ore then the cornparison Mr.Siemens is making would be a perfectly true one. But it happens to be the case that upon a comparison of the Clair- vale furnack blown with a hot and with a cold blast you find the volume of carbonic acid in the cold is considerably greater than that in the hot. Dr. Paul :If we compare two furnaces one worked with cold blast and burning fuel at the rate of two tons for each ton of iron produced and a hot blast furnace worked so that the con- sumption of the fuel is at the rate of only one ton for each ton of iron produced we must. remember that in fact the largest pro- portion altogether of the materials passing through those furnaces in both cases is the air by which the combustion is supported.Therefore taking it for granted that in both cases the discharged gases go away at the same temperature we have in the one Mast-furnace twice the amount of gaseous material passing through the furnace and twice the quantity of heat being carried off in that escaping gas. Therefore it is evident that the quantity going away to waste in the cold-blast furnace is twice as great as in the hot-blast furnace; and if we had the wast,e twice as much in the one case as it is in the other it is very elddent that in the hot-blast furnace there must be very considerable saving. Captain Noble With respect to the ratio between carboiiic acid and carhonic oxide in the waste gases Mr.Bell has found that within a very short time and while apparently the furnaces are working precisely the same there is a very great difference in their ratio. I entirely agree with what Mr. Bell CHEMISTRY OF THE BLAST-FURNACE. has said and I believe very little in the analyses of tunnel- head gases. The analyses of gases taken fiom pipes are I believe entirely fallacious. It is almost inipossible to believe that ratios in crooked lines like what we see on the diagram can really exist in a furnace arid it is very evident that when we take gas fiom a furnace by means of a small pipe the nature of that gas will change very much in accordance with the last substance with which the gas has come into contact- whether it be coke for example or whether it be ironstone.I have had occasion myself recently to make an invesbigation with reference to the determination of the number of units of heat produced in a furnace and what became of them. In so doing I have endeal-oured to trace the number of iinits of heat that go away with the tunnel-head gases and which are re-produced \&en the tunnel-head gases are burnt and so on. And finally I have worked it out in the work that is done by the engines and other means. The great variations that IUr. Bell has found in his analyses of the gases from the pipee is entirely confirmed in another way and that is by the amount of water vaporized. In the space of three or four hours the amount of water vaporized varied most eiiormously and if I remember right Mr.Bell found a variation in the ratio of the carbonic acid amounting to something like 20 per cent. of the whole amount. The ratio also varies much in the different furnaces. Mr. Crossley It is certainly surprising to find that iron absorbed carbon at so early a stage in the furnace. I have passed pure carbonic oxide over pure sesquioxide of iron and I never noticed any deposition of carbon ; and I am rather afraid that in the case of MY. Bell the calcined stone had not been fully calcined in the interior of the stone and perhaps the carbon which he obtained jn the deposit was the carbon which was left in the stone. Mr. B el 1 has also told us something which I consider very interesting in reference to the proportion of lime-stone that may be used in a furnace and he stated that the smaller the quantity of limestone used the larger the percentage of sulphur which comes off in the pig-iron.JVe tried some years ago some experiments in which we used 39 cwts. of lime- stone 7 cwts. and I believe 14 cwts. and we have found that the silicon and the sulphur in the iron came off in larger quantities in the iron where the smallest quantity of limestme UB I. LOWTHIAN BELL ON THE Was used and there was a smaller proportion of metallic bases in the pig-iron produced from the smallest quantity of limestone. Mr. Cochrane :I shall be glad to offer a few observations on the subject of hot blast which has been rather a pet subject with me for a great many years.I believe it ia an admitted fact that the colder oxygen is and of course the more dense it is the more intense is the action of combustion due to that oxygen and that there is no advantage in warming it. But not 150 I believe with nitrogen and of course with the mixture of atmospheric air. I think that the question of heating that mass of nitrogen has been rather overlooked in the paper; and not only has a large amount to be heated in the furnace but I believe a greater weight of nitrogen has to be heated for every ton of iron that is reduced. Mr. Bell has alluded to a dark appearance before the tuyere. It is notorious that this dark appearance extends in many instances to a long t'ube right into the centre of the cold-blast furnace; and that is really part and parcel of the heating apparatus which enables the blast to be delivered in the cold-blast furnace at the requisite temperature for the quality of iron required.Hence it needs the element of time of combustion to be taken into account or not the time of combustion rather but thatl the material-the coke-is iii being burnt higher in a cold-blast furnace by reason of the time required for heating all the nitrogen and so on than is the case in a hot-blast furnace where you start with temperature of we will say 1000" F. and where there is no longer any necessity for heating that blast inside the furnace. The zone of fiision is spread lower down the tuyeres and so pro tanto you gain in height of furnace. Mi..Bell I will not take up many minutes in replying to the questions which have been put befcre us. One point raised was as to the greater volume of gases escaping from a cold-blast furnace than from a hot. Well I have not given figures on that point because as I stated before I have intruded too long upon the compaiiy already. But it was of course im- possible to ascertain the quantity of heat escaping by the gases at a certain temperature unless I had known the quantity of gases escaping which was a necessary element in the calcu- latlion. With respect to the observations of Mr. Cross1 ey with regard to the possibility of the carbon in the ironstone being CHEMISTRY OF THE BLAST-FURNACE. the cause of the deposition of the carbon in the iron I would remind him that a certain temperature was required.If this carbon was deposited fiom the carbonic acid already existing in the iron ore how did it happen that it never found its way there when it was exposed merely in a blast-furnace having the escaping gases going out at a terr,perature something like melt- ing lead? There was an invariable connection between the temperature of the escaping gases and the appearance of this carbon. With regard to my friend MI-. Cochrane all I can say is this that I am not prepared to dispute whether it is better to heat the oxygen or better to heat the nitrogen. But t'his appears to me quite certain that as you look upon the blast as a mere vehicle for conveying the heat it is a matter of perfect indifference whether the heat is carried in by 8 lbs.of oxygen or 14 lbs. of nitrogen. I have made diagrams not from imagination but based upoii actual analyses of the gases to show that at a given point the whole. of the oxygen of the blast is absorbed and whether the blast went in hot or cold appeared to make no difference. The carbonic acid was as readily reduced to the condition of carbonic oxide in the hot blast as in the cold. The figures before you illustrate quite truly the temperature of the gases as they were coming from two furnaces and at different periods of the day and they merely show the irregu- larity of action of all blast furnaces and how impossible it is from a few observations to draw any general expression as to their action.The President I am sure we must feel greatly indebted to Mr. Bell for hip exceedingly able exposition. Two or three things have certainly become clear ;in the first place that a saving must be effected by replacing as much as possible that imperfect combustion which takes place in the furnace by the more perfect combustion wliicli may be effected outside the furnace when it is applied to heating the blast. That there must be a saving in that way is obvious. I remember it was aome years ago t.hat Mi*. Siemens drew my attention to that as a necessary source of saving in the utilization of hot blast and certainly it was from him that I first learned that circum- stance as bearing upon it. Another exceedingly weighty cir- cumstance which we now at all events-or I for my own part -learn to consider in relation to this from Mr.Bell is the SCHORLEMMER ON THE CONSTITUTION difference of the charge of the furnace under the two coiidi- tions. If we have less coal present in the furnace in proportion to the ore or in other words if we have more ore in propor- tion to the coal we have a greater quantity of good heat- absorbing substance. That tells in two ways as Mr. Bell has exceedingly well shown iiot only by absorbitig the sensible heat of these two gases but also by burning some of the carbonic oxide which would otherwise have escaped unburnt. I think it is of particularinterest that Mr. Bell has proved that the gases at the temperature of combustion at which they usually escape are capable of reducing a great deal of oxide of iron; and that does seem to me to point to a direction in which we may effect improvement in these furnaces.

ISSN:0368-1769    

DOI:10.1039/JS8692200203

出版商:RSC    

年代:1869

数据来源: RSC

摘要:

SCHORLEMMER ON THE CONSTITUTION XIX-On. the Constitution of Hyposulphurous Acid. By C. SCHORLEMMER. (Read May 20th 1869.) IN a paper on the Synthesis of Formic and Hyposulphurous Acids published in the Journal of the Chemical Society N.S. v. 291 Dr. Duprd describes some experiments from which he infers that formic acid and hyposulphurous acids have an analogons constitution hyposulphurous acid being in fact formic acid in which the carbon is replaced by sulphur and vice vem& He finds a support of this view in the obGervation of Rose that no hyposulphite is capable of existing which does not contain at least one atom of hydrogen and he proposes therefore to reduce the molecular weight of hyposulphurous acid to one half. Dr. Odling has lately expressed similar views;* he also advocates t,he halving of the molecular formula and con- siders hyposulphurous acid as a hydracid in whicli only one atom of hydrogen is replaceable by a metal; sulphuric acid beirig an oxyacid and sulphurous acid standing between the two.Hyposulphurous. Sulphurous. Sulphuric. f Joiirn. Chem. SOC. ser. 2 vol. vii 180. OF HYPOSULPHUROUS ACID. Froin this it uppears not to be well known that Rose's statement that hyposulphites containing no hydrogen do not exist is incorrect. This was shown by Pape,* who found that a,ll the hydrogen is present in the form of water of crystallisa- tion which by taking proper care can be expelled completely without the salt undergoing decomposition the only difficulty being that the temperature at which the last portion of the water is driven off is only a few degrees below that at which decomposition begins.Thus the sodium potassium and barium salts can be obtained quite anhydrous by heating them up to 215' C. At 220°-225" or only 5' higher the salts begin to decompose with separation of sulphur. The lead-salt loses all its water at looo but oiily at a few degrees above this temperature it begins to blacken. The formulae of these salts are therefore Na2S20,; K2S20,; BaS20 ; PbS,O,. Moreover there are other reasons which show that the molecule of hyposulphurons acid contains two atoms of sulphur. In a great many of its reactions it splits up in such a way that the atom of sulphur which was previoudy contained in the sulphur dioxide remains in the oxidized state whilst the other atom geparates as free sulphur or as a sulphide.Na2S203+ 2HC1 = 2NaC1 + H20 + SO + S. Ag2S,0 + H20 = Ag2S + H2S0,. Hg2(N03)2+ Na2S,0 + H,O = 2E" + Hg,S + Na,SO,. From these reasons it follows that we must retain the old for-mula for hyposulphurous acid anti consider it as Dr. Odling first proposed fourteen years ago,f as sulphuric acid in which one atom of oxygen has been replaced by sulphur both being derived from sulphurous acid the former by adding to it one atom of sulphur and the latter by the addition of one atom of oxygen. Sulphurous. Hyposulphurous. Sulphuric. * Poggendorff. Ann. cxxii 408. t Quart. Journ. Chem. SOC. vii 8. SCHORLEMMER ON THE CONSTITUTION Dr.0dling referred to the discussion which followed the paper by Professor Stoke s ‘‘On a certain reaction of Quinine,”” in which it was shown that as a general rule the halogen salts of quinine or those salts in which the quinine (or the quinium) is not directly combined with oxygen do not mani- fest fluorescence whereas such salts as the sulphate and nitrate which are essentially oxygen salts do exhibit fluorescence. But there is a remarkable exception in the case of the hypo- sulphite which though ordinarily regarded as an oxygen salt is not at all fluorescent. With reference to this point he (Dr. Odling) ventured on that occasion to reinark that it was possible that the compounds of hyposulphurous acid might be after all not oxygen but halogen salts; and in favour of that view he mentioned the observation of Rose quoted in Mr.Schorlemmer’s paper not being then aware that this observation had been refuted. On the present occasion he would like to call to mind the different views which had been put forward with regard to the hyposulphites. Looking to empirical formula only sulphate of sodium is represented as Na,SO,. The pentasulphide of sodium has the formula Na,S in which the S may be taken to correspond with the S and the 0 of the sulphate. Between these there might be three intermediate salts maldng the series Na,SO Na2S203 Na2S30, Ns,S,O Na& a series which appears very natural and likely to exist. The first of t.he intermediate salts viz. Na,S20, is the ordinary hyposulphite of sodium.The second is described in Sir Robert Kane’s “Manual of Chemistry,” where it is said to crystallise witJh the same number of atoms of water as the hyposulphite and to be isomorphous therewith. The third intermediate compound Na,S,O does not a.ppear to have been obtained. If now we oxidize sulphite of sodium Na,SO, we obtain the sulphate Na,SO,; and if instead of oxidizing it we sul- phurize it, we convert it into the hyposulphite Na2S,03 * Page 1’74of this volume. OF RPPOSULPHUROUS ACID. 257 there ia therefore an analogy between the sulphate and the hyposulphite both in t,he ultimate formule and in this par-ticular mode of formation. On the other hand Professor Kolbe succeeded in making formic acid by reducing carbonic acid with sodium thus :-H,CO + Na = NaHCO + EaHO.Carbonic Formate of Hjdrate acid. sodium. of sodium. This reaction appears at first sight very similar to the ordinary reaction by which a hyposulphite is obtained by the action of metals on sulphurous acid. The hyposulphite can be produced readily by dissolving zinc or iron in sul-phurous acid; and if sodium were used as in Professor Kolbe’s reaction a result would be obtained which might be expressed by the equation H$O + Na = NaHSO + NaHO the caustic soda remaining combined with the excess of sul-phurous acid employed. This fact led Dr. DuprA to foim the opinion that formic arid hyposulphurous acids are analogous compounds. He (Dr. Duprd) made several experiments by acting upon carbonates with carbon and the results of these experiments induced him to believe that he actually produced formic acid; but these experiments as Dr.Duprd himself acknowledged could not be considered as altogether coiiclu- sive. With regard to formic acid all experimental evidence tends to show that in this acid the carbon is united with oxygen with hydrogen and also with oxygen already com- bined wit’h hydrogen being in fact represented by the for- mula H(H0)CO. But if it be right to say that hyposiilpliurous acid is not an oxygen acid it must be represented by the formula HHSO, in which both the hydrogen atoms are directly combined with sulphur. In fhvour of this latter view Professor Stokes on the occasion above referred to adduced the ex- ceptional fluorescence of the quinine salts of hyposulphurous acid and some other reactions which will be found in his paper ;* and he (Dr.0dling) supplemented those remarks by referring to the singular habits which the hyposulphites have of forming double salts exactly analogous to the double Page 178 of this volume. SCHORLEMMER ON HYPOSULPHUROUS ACID. chlorides for example the double hyposulphite of silver and sodium and the double hyposulphite of gold aiid sodium. The reactions adduced by Mr.Schorlemmer in which hypo- sulphurous acid shows so great a tendency to split up in such a manner as to yield one atom of sulphur still in the oxidized state while the other makes its appearance as free sulphur or as EL sulphide appear to him (Dr.Odling) as equally explicable on either formula. Taking for example the re-action with hydrochloric acid we have on the one view (Mr. Schorlemmer's) Na,S,O -t 2HC1 = 2NaC1 +H,O + SO + S and the other 2NaHS0 + 2HC1 = 2NaCl + 2H,O + SO + S. The tendency of a hyposulphite to fiirnish a sulphate and a sulphide is strictly parallel to that of a hypophosphite or phos-phite to yield a phosphate and a phosphide. Moreover the mode of formation of hypophosphites is analogous to one mode of formation of hyposulpl-ites. With regard to the molecule of water in the hyposul-phites Dr. Odling said that if we represent hyposulphite of sodium according to the older view we have the formula Na,S,O,.H,O ; he however preferred to write it 2NaHS0,.The salt retains its molecule of water wit,h great firmness re- q~ing a heat of 215' to drive it off. The sodium silver and barium salts also require this unusually high temperature to dehydrate them. This however does not prove absolutely that the molecule of water in question is different from water of crystallisation though it is in favour of that view ; and tJhe reaction may be precisely similar to that by which at a SUE-ciently high temperature two molecules of acid sulphate of sodium 2NaHSO, lose a molecule of water to furnish the salt Na,S,O,. He had said relying up011 Rose's statement that it was impossible to drive off the corresponding molecule of water from a hyposulphite; but now corrected by Mr. Schor-lemmer he would merely say that was difficult.Dr. Odling concluded by saying that the question is one on which he retains his mind quite ready to bend in either direction as fresh facts may arise ; but that at present he does not think that there are sufficient facts to enable us to decide the question absolutely either one way or the other. FIELD ON SULPHATE OF ALUMINA FRON IQUIQUE. 259 The President expressed his opinion that there were two or three points brought forward by Mr. Schorlemmer which were entitled to some weight. First there is the tendency of hyposulphurous acid to form double salts. Now among the characteristics of bibasic acids this tendency is as a rule one of the most coiiclusive and he (the President) thought that in the case under consideratioii it ought to have consider- able weight in favour of the bigger forinula.With reference to t.he decomposition of hypodphurous acid into sulphur and sulphurous acid it occurred to him that there is a difference in degree between regarding this decomposition as resulting from the splitting up of one molecule and regarding it as proceeding from a reaction between two molecules. We know for ex- ample that water is much more easily eliminated by heating a bibasic acid tha,n by the mutual action of two molecules oE a monobasic acid; and there are other cases which would lead us to assume that the result is due to an action taking place in one molecule rather tliau in two.

ISSN:0368-1769    

DOI:10.1039/JS8692200254

出版商:RSC    

年代:1869

数据来源: RSC

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FWLD ON SULPHATE OF ALUMINA FRON IQUIQUE. 259 XX.-Note on Sulphate of Alumina from Iquipue Peru. By F. FIELD, F.R.S. (Read May 20th 1869.) THEfollowing is an aiialysis of a fine sample of native sulphate of alumina from Peru after deducting srriall quantities of chlo-ride of sodium oxide of iron and silica :-Sulpliuiic acid.. ...................... 35.56 Alumina ............................ 15.88 Water .............................. 48.56 100~00 corresponding to the formula A1,0,3S03 + 18H0 which requirerj Sulphuric acid ........................ 35-93 Alumina ........................... 15.57 Water .............................. 48.50 100*00

ISSN:0368-1769    

DOI:10.1039/JS8692200259

出版商:RSC    

年代:1869

数据来源: RSC