111 TECHNICAL CHEMISTRY Technical Chemistry. Chemical Examination of Twelve Colours found at Pompei. By P. PALxE R I (Gazxetta c7Limica itrcliaiza vi 39-45) .-Of these colours three were yellow one consisting of a yellow ferruginous earth mixed with white clay to make it paler ; another a limonite (hydro- carbonate of iron) mixed with gypsum; the tliird a yellow ochre mixed with calcium carbonate. Of the two greens one a bright g.reen was found to contain ferrous and ferric oxides alumina lime silica and carbonic anhydride. It is apparently identical with “ terra zrertle,” which Pliny mentions (xxxv 29). “ Sunt etiamnum novitii duo colores et vilissimi; viride quod Appianum vocatur. . . . Fit et ex creta viridi.” The other green contained copper but from its state of aggregation the author thinks it must have become considerably altered in the lapse of time.Five red and red-brown colours were found to be ochres ; one probably “mhio faZso,” the “9ni71iuwb secun-da~i~?z’’ of Pliny; another sample was a mixture of fragments of various descriptions and the twelfth whicli was of a rose colour was found to consist of a white clay mixed with a little chalk and phos- phate and coloured with a rose colour of organic nature. ItlForms a purple lake with alumina and its reactions when compared with those of cochineal and madder lakes exhibit a marked discrepancy in several instances especially under the action of chlorine and bromine the Pompeian colour being exceedingly stable. The author is of opinion judging from various statements in Pliny the text of which he quotes that it is not improbable that this extremely solid and fast rose-colour employed by the Pompeians may Lave been obtained by saturating a white clay with the compound colour produced from Tyrian purple (from Pzcrpura or Jfurex) extract of Kermes (Coccus ILicis from Querczis coccijera) and madder extract This point he hopes to deter- mine experimentally.C. E. G. Temperature and Composition of Gases evolved from Ultra-marine Furnaces. By F. FISCHER (Dhzgl. pol@ J. ccxxi 468-473).-The temperatiire of the ovens mas ascertained with a Siemen’s electric pyrometer (Dingl. J. 1875 217 29l) and the composition of the gases escaping determined by Orsat’s apparatus which has been recently improved by Aron.The fact that the absorption and the measurement of the gases take place i3 two distinct tubes by which the determination of the separate constituents in the gas after it has been measured is greatly facilitated renders this apparatus more suitable for analysis than the use of Winkler’s burette. The sul- phurous acid was determined with normal iodine solution. The acids absorbable by potash were determined by Orsat’s apparatus using oil as the indicator so as to prevent the solution of sulphurous acid in water. The difference of the two determinations is calculated as carbonic acid but since the gases are always coloured more or less white from the presence of sulphuric anhydride which is also absorbed by potash lye the percentage of carbonic acid will be somewhat high.ABSTRACTS OF CHEMICAL PAPERS. The following fable gives the results of analyses made with ;Icrucible furnace :-Crucible Furnaces lighted at 6 a.m. -No. of Experi-Time. sop coz. 20 0. N. Cempera Remarks. ture. ment. ----_ --4th Jnly our. min 1 90 2 -67 9 *93 0 6 *4 81 .o Fire burnt down. White vapours. 2 9 30 2 -5s 10 -12 0 7'1 80 2 473 Ditto. Ditto. Dampers 3 10 30 3.28 12 '12 0 4 '8 79 -8 522 { partly closed. 4 11 0 2 *89 10 '01 0 6 '2 80.9 696 Ditto. -5 11 30 3.04 8 -26 0 8 .7 80 .O Ditto. 6 12 0 2 *'76 10 -5.4 0 6.2 80 .5 -Ditto. 7 12 40 2 '10 10.80 0 6 *O 81-1 700 Ditto. 8 2 50 2 '27 12.63 0 3 '0 82 .1 Air shut off by -{ layers of brichs. Immediately after 9 3 40 3 *12 17.88 0 0 79 .o -il stoking.Vapoiirs not white.Upper layer of bricks removed 10 3 47 2.95 13*05 0 2'1 81 *9 733 { thus allowing more air to pass tl1rough. Imniediatelg aft er stoking. Slight 11 40 3 *25 -0 * 0 -4 81 -1 -{ separation of f soot. Not stoked ;there-I fore burnt com-12 4 20 1 '48 -0 0 -4 82 *5 pletely. Vapou1-s white not trans- -1 L p:irent . About 10 minutcs 13 4 40 1*40 -0 4 .8 82 '6 714 { after stoking. 14 5 10 0 '73 -0 3 .8 81 -7 Completely burnt. Vnpours white. Ditto. Air slint 15 5 45 0 -34 -0 6.3 SO -8 668 { Off. 16 6 10 0 '47 -0 1 -1 82 -5 -Ditto. 17 G 16 1*11 -0 3.4 81 '1 Immediately after stoking. -i R'ot stoked ;burnt 3.8 6 30 0 *64 -0 0 *1 83-1 '30 { 5th July completely.Not stoked for 0 p.m. hours ; all open- 19 50 0.01 -0 7.9 80 *4 627 ings shut off by clay. -It seems that the temperature of the furnaces during the ultramarine process is about 700". The gas analyses show that the process is more quickly conducted in crucible furnaces than in mufHe furnaces. It is next to impossible to use the gas mixture profitably for the lead- TECHNICAL CHEMISTRY. chamber process as the gases are very much diluted and are not evolved regularly. The reason why a crucible furnace requires 50 kilos. and a muffle furnace 146 kilos. of best Westphalian coal for every 100 kilos. of blue charge is sufficiently explained by the fact that through the latter form of furnace a larger quantity of air is always passed.Carbonic oxide is mostly absent in these gases. D. B. MEK (Dingl. YoZyt. J. ccxxi, Hardening of Steel. By A. JAEULI 436-446).-1t is stated that boiliiig water does not form tlhe only cooling liquid which hardens steel but that under circumstances water at a temperature of 150" or more will do so and that boiling hot oil fluid lend fluid tin and even fluid zinc-a cooling liquid of about 400" of heat-will also give similar results. This latter fact is worthy of notice as it has in general been assumed that steel cannot be har- dened unless it be brought down very quickly to a much lower tem- perature and that hardened steel softens considerably when exposed to a temperature of 300" ; but experiments have shown that the hardness of steel depends upon the quickness with which it is reduced from a temperature of about 500" to one somewhat under 500".Although the above-mentioned metals are able to harden steel it was iiever- theless found that their hardening property could not at all be compared with that of water this property being in fact influenced not merely by the temperature and the conductivity of the cooling substance but also by its capacity for heat its boiling point and in the case of a low boiling point by the amount of latent heat tvhicl.1 the vapour contains. For instance alcohol vaporises very readily and as it contains but little iatent heat hardens steel but very badly. Now it is well known that a metal which is heated to a temperature of 1000" or even only to 500" must be surrounded by a temperature which renders the existence of water of an ordinary pressure quite impossible.So long as hardened steel possesses this temperature-which it in fact retains until its hardening commences- it cannot be in immediate contact with water and when plunged into that liquid must be surrounded by a layer of vapour which is apt to hold back portions of water near the steel and thus prevent a regular liardening of the latter. It is of course improbable that under these circumstances the steel would give up its heat to the water by direct conduction and as the layer of steam between the metal and the water cannot be superheated to any material extent at so slight a pressure we must suppose that the water becomes heated by radiation the layer of water separated by the steel evolving a constant stream of vapour which condenses on the upper portions of the layer of water.It is shown by calculation that one kilo. of steel requires about 0.2 kilo. of water at 20" to lower its temperature from 1000" to 300'; but the reason why a much larger quantity of water is actually required is sufficiently explained if we consider that (I) the steel has to be moved about in the water ; otherwise the formation of vaponrs would prevent its hardening. (Relying on this fact it was possible to harden steel under hot water alcohol or turpentine.) (2.) The vapours con- dense in the water and heat a small quantity of it too strongly. Thus it seems that it would be possible to harden steel with a small VOL.XXSI. I ABSTRACTS OF CHEMICAL PAPERS. quantity of water could the vapour escape as quickly as it is formed. S~ich however is not the case and the above condensation can there- fore be facilitated only by the following Gperations :-(1.) By pluiqing the hot steel slowly into the water the surface of the latter 1s cliietly acted upon the vapours having easy access of escape in the air. This method is applicable in cases where the metal above the water remains sufficiently hot to be hardened ey. files and other similar articles are easily hardened by this process. (2.) A hot and powerful stream of water escaping from a steam-boiler or an ordinary stream of water facilitates the hardening by carrying off the vapours as quickly as they are formed.(3.) The most satisfactory method is that by which the steel is hardened by means of a thin spray. In this con-dition the water is largely mixed with air which having a very quick and strong action not only occasions a quick vaporisation but also c*aiTiesoff the vapour formed in a much more complete way than any of the above-mentioned agents. In practice the degree of hardness of steel depends upon the annealing of the lntter-a process which alwnps follows the hardening operations. In order to obtain a medium hard- ness the steel is cooled slowly throughout the whole of the operation or it is cooled very quickly to 400° and afterwards slowly. The former method did not answer in practice a quick cooling being almost indispensable if satisfactory results are to be obtained.The resulting steel was either of a very hard or of a very soft nature. With regard to the annealing methods similar experiments were undertaken the results of which seemed to show that the mosi pro-fitable form of applying the cooling liquid was when a spray of water 51-as blown on to the steel. In conclusion it is stated that fused metals especially tin answer very well for hardening small articles. The author was able to harden a steel wire 3 mm. thick in a tin bath of 400" of heat the wire again becoming soft when it was left in a bath of 350". On account of the smaller heat-capacity of tin a large quantity of it is re-quired. One part of steel requires about 45 parts of tin to cool it from 1000" to 300° if the temperature of the bath before use is 250° aid has not to be raised over 300".In another paper a description of tlie fusion of the steel before it is hardened and further results with regard to the above operations will be given. D. B. Burnishing of Iron. By P. HESS(Dingl. polyt. J. ccxxi 94-95).-The surface of the iron is painted over with linseed oil and heated whereby together with separated carbon ferroso-ferric oxide appears to be produced which forms the essential protecting layer. Articles which cannot be heated may be dipped into an acidulated solution of ferric chloride whereby a black layer of ferroso-f erric oxide is formed which when dipped into hot water becomes firmly fixed on the iron SO that after drying it can be rubbed with linseed oil.The formation of this layer takes place by the reducing action of the iron on the oxide and its salts 4Fe203+ Fe = 3F304. The advantages of burnishing with ferroso-ferric oxide (magnetic iron ore or smithy scale burnishing) consists in the fact that it is done much more quickly than the burnishing with ferric oxide and that it TECHNICAL CHEMISTRY. 115 is more beneficial to the iron than the latter. By using cuprous snl-phide a fine bluish-black layer is obtained which forms a good protec- tion against rusting. The iron has only to be placed in a solution of cupric sullphate for a few minutes until a fine copper coating is formed on its surface which after having been washed with water is treated with a solution of sodium hyposulphite (thiosulphate) slightly acidu- lated with hydrochloric ncid when a bluish-black coating of cuprous sulphide is obtaiued which is unaffected by air and water.The sur- face is then washed with water dried and polished. D. €3. The Uses of Patent Golours. By R. GLANZMANN (Dim$. po&. J. ccxxi 4i3-47 7) .-On accouut of their simple application their perfect coloration and their cheapness the patent colours described by Croissant and BrdxmniBre are now largely used in the dyeing of yarns. These organic colours containing large quantities of sulphur are manufactured by various firms and under differelit names. The author described (BUZZ de Bown 1876 61) a prepara-tion which was broiight into commerce by Poirrier under the name of "Cachou de I~aval." It seems to be prepared from sawdust and is in the form of large blackish-blue very porous lumps which are very hygroscopic smell strongly of sulpliuretted hydrogen and contain 14 to 2 per cent.of water. It is very readily soluble in water its aqueous solution having a strongly alkaline reaction and being pre-cipitated by acids with evolution of sulphuretted hydrogen elimina- tion of sulphur and formation of a darkish brown precipitate difficiiltly soluble in alkalis. In spite of the valuable property which this colouring matter shares with the other patent colours of being fixable on cotton without the use of a mordant or even without steam and in spite of their resistance to the action of light acids and soaps the author has nevertheless come to the conclusion that this category of colours will not find much application to the printing on cotton.These colours are easily acted upon by chlorine and do not form shades which are much valued for cotton prints. Glanzmann has made several dye experiments with Poirrier's " Cachou de Laval," and has obtained very good results from the " dark cachou " which he produced in a bath of 50 grams of colouring matter fixed by a solution of 5 grams of potassium bichromate in 1 liter A bath containing 3 gmms of colouring matter in 1 liter yields after treatment with potassium chromate a light grey colour with a yellow tinge. By dissolving 10 grams of the cachou in water mixing the solution with 20 grams of real cachou (dissolved in 10 C.C.of soda-lye of 1.208 sp. gr. and 500 C.C. of water) and making the total up to 1000 c.c. yarn acquires a fine dark bronze colour when it is left in this bath at 7.5" for a quarter of an hour and aft'erwards fixed with the chromate or still better with a nitric acid bath of 2" B. The various shades resulting from the colouring bath are greatly influenced by the fixation bath. Potassium bichromate gives the darkest sliade of colour ; nitric acid and nitrate of iron with lead acetate give a grey colour having a slight yellow tinge; ferrous sulphate (5 grams in 1liter) with sul-phuric acid of 1.004 sp. gr. or better copper vitriol (5 grams in 1liter) give a pep with a blue tinge. This shade forms the main use 116 ABSTRACTS OF CHEMICAL PAPERS.of the patent colours serving as a ground colonr for indigo blue by which a considerable saving of valuable colouring matter is occasioned whereas the stability of the blue is not in the least injured. In Ger-many this colour is sold in the form of a liquid under the name of "Indigoersatz " (indigo substitute). In the Deutsche Ind?c.styie-Zeitzbng 1876 43 a description of a second use of this shade as a finishing colonr for chemical blues is given. Yarns either white or steeped are passed through a solution of nitrate of iron rendered blue by yellow prussiate of potash and finished with indigo substitute. The yarn patt,erns dyed in this manner obtain either a deep black or a very fine bluish-black colour. The former colour is obtained by leaving 25 kilos.of boiled yarn in a bath of sumach (-5 kilos.) for 12 hours and then in a bath of nitratle and lignate of iron (2 kilos. of nitrate of 1.525 sp. gr. and 3 kilos. of lignate of 1.133 sp. gr.) for half an hour. The yarn is brought into a chrome bath (350 grams of red potassium chromate) and lastly dyed in a hot bath of indigo substitute (2.5 kilos.) to which 250 grams of quercitron extract has been added. After washing with soap the yarn is washed with water and dried. The bluish-black shade is obtained by allowing the same quantity of yarn to remain in a bath of 5 kilos. of sumach for 12 hours then in a bath containing 5 kilos. of nitrate of iron. It is brought into a bath of 1.5 kilo. of yellow potassium prussiate to which 0.5 kilo. of hydrochloric acid are added and having passed it though this bath 2.5 kilos.of nitrate of iron are added to the latter and the yarn treated therewith. Its further treatment in the chronie bath and the indigo-substitute baths (3 kilos.) is analogous to that of the black dye. D. B. The Present State of the Sugar Industry in France and a few Experiments on the Use of Lime in the Clarifying Process. By A. LAMY (Dingl. yo7yt. J. ccxxi 64-68).-After point-ing out thatl the manufacture of sugar in France has of late years become less profitable than formerly in consequence of the great excess of production over home consumption and the keen competition in foreign markets the author proceeds to indicate the methods which appear to him best adapted to remedy the evil.These are :-1. The endeavour on the part of the cultivator to produce roots containing a large percentage of sugar rather than roots of great size. 2. Increased attention to the methods of extracting and purifying the juice. The French beetroot contains onlyfrom 5 to 6 per cent. of its weight of sugar whereas from German and Austrian roots 7 to 8 per cent. are obtained ; but experience has shown that with proper care a root of the same richness in sugar can be produced in France. Manufacturers have until recently bought the root according to its weight alone without taking into consideration the percentage of sup- and to increase their crop many farmers have employed seeds or chemical manures which were favourable to the formation of large roots.In Germany how- ever the mode of levying the duty does not induce farmers to obtain a large bulk of material but to obtain a large percentage of sngar in comparatively a small quantity of roots. The second and third conditions which require improvement in that country are the TECHNICAL CHEMISTRY. extraction and the chemical purification of the sap. In a recent paper M. Phsier discussed the excessive use of lime in the clarifying process. The considerable increase in the weight of the scum which contains about 50 per cent. of the sap occasions a loss amounting to 200 kilos. for every 100,000 kilos. of roots. To justify the use of this excess of lime it is usual to allege the fineness of the white sugar of first crystallisation thereby obtained the quick and complete decolori- sation of the sap and the necessity of fixing with the lime the total quantity of sugar in the form of a saccharate.But although the existence of a lime saccharate at a temperature of 35" has been generally assumed it has never been proved. PBsier has made a large number of alkalimetric determinations the results of which seemed to show that at a temperature of 35" a saccharate does not exist still less therefore at 60" or 70" at which temperature the acldi- tion of the lime takes place. With the view of clewing up these contradictions Lamy undertook the following experiments. In the first place the quantity of lime was determined which would dissolve 100 parts of a 10 per cent. sugar-solution at SO" 50° GO" 70" and loo" if 1to 2 per cent.of lime were added a proportion generally taken in practice. The slaked lime and the sugar-solution were mixed at the hrial temperature and left in contact for three hours with frequent shaking. The same quantities of lime were added at SO" GO" and iO" the temperature allowed to rise gradually to loo" and the liquid filtered very quickly at this temperature. The lime in solution was then titrated. The results are shown in the following table :-Solubility of Lime in a lop. c. Sugar Solution using 2 yarns of Liwe for 100 parts of the &olution. . _c_- 100 grams. 15-5 gimns. + 139.5 70 23 *O + 133 -9 50 53 -0 + 105'6 30 120-0 + 80-7 15* 215 -0 -53.0 0 250 *O -87.0 50-100 18*5 -I-136*5 60-100 17 *O + 138 '0 70-100 16'0 + 139 .0 * The numbers corresponding with the temparatures 15' by saturating the sugar-solutions with an excess of lime.and O" were obtained I2 ABSTRACTS OF CHEMICAL PAPERS. The conclusions to be drawn herefrom are :-(1.) The quantity of lime dissolved in the sugar-solution increases in the same ratio as the temperature decreases. The same applies to the solution of lime in pure water. (2.) By deducting the quantities of lime dissolved in sugar-water (col. 2) from those dissolved by pure water (col. 3) at the same temperature numbers are obtained which correspond with the absorp- tion of the lime by the sugar alone. It is strange however that these numbers vary with the temperature and are much higher than those corresponding with the solution of lirne in pure water.(3.) By comparing the numbers in column 4with 149 of column 5-a number which gives the quantity of lime to be dissolved so as to form a monobasic saccharate-we find that tbey are lower than tliis and so much the more the higher the temperature is than 30". The slight differences of the numbers in colnmn 6 which correspond with the temperatures loo" 50-100" 70-lOO" are suEciently explained by the difference of time during which the solutions were kept at loo" and by the difficulty 3f obtaining a saturation at this temperature. (4.)The quantity of lime absorbed by the 10 per cent. sugar solu-tion may rise with the fall of the temperature so mnch that at O" for example it surpasses the quantity necessary for the formation of a monobasic saccharate more than 50 per cent.With regard to pure sugar-solutions therefore the quantity of fixed lime is larger than that which pure water disswlves at the same temperature and even at 100" ; but it is much lower than that necessary for forming a monobasic sac- charate at 30-70". In conclusion Lamy gives a description of Marot's new method which is based on the idea that it is not the true mineral salts which hinder the manufacture of sugar but rather the salts with mineral bases which are combined with organic acids and neutral bodies. The organic substances left in the sugar through faulty treatment have in- duced Marot to give up the use of lime and baryts salts in order to carry out the refining with a minimum of lime (5 per cent.).Marot boils the solution after having added the lime until its volume has been reduced to one-fifth expecting thereby to decompose the nit'ro- genous substances and to liberate the resulting ammonia. Witli regard to the probable success of this process it is to be observed that soluble lime salts and lactates must remain behind after the purification of the juice by this treatment and it is by no means proved that all the nitrogen is thereby removed. Analyses of the juices thus treated and of the boiled masses are the only means of judging whether the yield is increased and whether the method is to be pre-ferred to the ordinary process. D. B. Use of Hydrochloric Acid in the Diffusion-process. (Dingl. yotyt.J. ccxxi 92) .-At several sugar refineries the so-called "bad pressing," i.e. a more difficult and slow circulation of the sap hhrough the layers has already been noticed during the diffusion and Erk showed last year how after a normal working of two months this bad pressing came on to such an extent that instead of 125 tons only 42.5 tons of bectroots could be worked in one layer. TECHNICAL CHEMISTRY. 119 For every pan of 3,000 liters of contents or 2,500 kilos. of charge, 1.5 to 2 liters of 40 per cent. hydrochloric acid diluted with an equal bulk of water was added which at once produced a normal pressing. This action seems to depend on the fact that certain organic sub-stances coagulate and are rendered insoluble by the acid. D.B. Myall-wood. By J. MOELLER (DingZ. poZyt. J.,ccxxi 153- 156).-At the present time a species of wood imported froni Australia is largely used in commerce under the above name and forms a substitute in the manufacture of the well-known briar pipes. At the ordinary temperature this wood smells very strongly of yiolets ; it is very hard and heavy and does not split regularly. Its spec. grav. is 1.578. When dried at loo" it yields 11.25 per cent. of ash containing the following percentage ingredients :-Silicic acid .................... 0.401 Carbonic acid .................. 43.721 Sulphuric acid ................ 0.488 Phosphoric acid. ............... 0.103 Chlorine ...................... 0.0'38 Potash. ...................... 2.621 Soda ........................2.054 Lime ........................ 47.533 Magnesia. ..................... 3.879 100.893 Deduct the quantity of oxygen equivalent to the chlorine.. .... 0-022 100.876 D. B. Carboazotin a new Explosive Substance. (DiizgZ. polyt. J. ccxxi 94).-hccording to Cahuc and Soulages a mixture of-50-64 parts of potassium nitrate (sodium or lime), 13-16 , sulphur 14-16 , tan 9-18 , soot lampblack &c. 4-5 , iron vitriol is heated with a corresponding quantity of water at 110-120" the liquid cooled the solid mass dried and brought into forms &c. According to the English patent of Faure and Trench a mixture of 1part of charcoal 16 parts of barium nitrate and 1part of uitro-cellulose are made up with water to a pulp then formed into cakes and dried.D. B. Manufacture Qf Yeast. By F. VAN HEUMEN VAN and W. €I. HASs E Lrr (Dingl. polyt. J. ccxxi 451-465).-Yeast is now prepared according to one of the following methods :-1. Dutch Xethod.-In Holland a tax is levied on the spirit pro-duced whereas the coops and apparatus are free from ltaxes ; hence in that country it is advantageous to carry on the fermentation in a ABSTRACTS OF CHEJUCAL PSPERS. large number of vessels. The raw material is always rye- and barley- malt. These substances are ground to a fine powder and washed with hot water until a temperature of about 65" has been reached. The mixture after the lapse of 1-2 hours is cooled to 37" with clear brewer's wash and then to 30-33" witli water at wliich temperatures the yeast is added.The fermentation commences gradually and goes on so slowly that the returns and the other insoluble substances are deposited. After three hours' standing the liquid is rim off and pumped into a shallow square vessel whereby the temperature is lowered to about 20". The actual fermentation and formation of yeast takes place in this vessel two layers of yeast being formed the one on the surface of the liquid and the other at the bottom of the vessel. The clear liquid between the two layers is after the termi- nation of this fermentation drawn off and brought back to the first mashing vessel where its fermentation is completed with that of the returns left behind. The yeast is brought into smaller vemels -"vhere after depositing it is sifted washed and pressed.The vessels used hold about 2,200 liters in which 93 kilos. of rye and 95 kilos. of malt are mashed. From 100 kilos. of flour 10 to 12 kilos. of yeast and 26-28 liters of spirit of 100 p. c. are obtained. The mash obtained varies from 62.5 to 67 per cent. 2. German Xethod.-In Germany spirits are not taxed but vessels and apparatus taxed very heavily which circumstance renders it necessary to occupy as little space as possible for fermenting vessels and other apparatus. Besides rye and malt maize is also used which on account of its hardness requires to be boiled in water for 1-2 hours before it can be used. The hot maize is added to the mash of rye and malt at a temperature of 65" and after saccharification cooled to 37".The mass is then run into the fermenting vessels cooled with clear wash and treated with yeast. After the fermentation has ter- minated the mass is separated from the returns by sifting and mixed with water. The mixture is again filtered and washed and the yeast after sett'ling is pressed while the cold mash on the top of the yeast is again pumped into the fermenting vessels and allowed to stand for two dnye. After this the fernientation is finished. The liquid can now be distilled off. In one hectoliter of space 13.88kilos. of flour (70 p. c. maize and rye and 30 p. c. malt) are mashed; 50 litres of wash are required for cooling purposes and the mash obtaiiied is equal to 67 p. c. of extract. 100 kilos. of raw material give from 9 to 10 kilos.of yeast and 28 to 30 liters of spirits of 100 p. c. 3. Afethod with Clear MaslL.-By this method a product of great purity and strength is obtained which has proved to form an excellent article in panary fermentation and is of' great importance to bakers wlio very often have orily a limited space at their disposal and require a substance which raises the dough very readily. 20 p.c. of rye 30 p. c. of maize and 50 p. c. of barley-malt are mashed in a vessel at the bottom of which a perforated plate is placed under which a cock is fixed for letting off the liquid. After the sacctiaritication is finished the clear mash is drawn off at the bottom of the vessel and the returns are washed with hot water. The filtrate is then cooled to 2T" and the yeast added.The mash after fermentation is pumped TECHNICAL CHEMISTRY. into a shallow vessel where the yeast is deposited. The clear mash is then taken back into the fermenting vessel and the yeast obtained is washed and pressed. For 1 kilo. of grain about 7.5 liters of mash are obtained equal to about 56 p. c. of extract. The yield of yeast is calculated at 9 p. c. that of spirit (100 p. c.) at 24-25 p. c. With regard to the raw material the method (2) is the most profit- able as less malt is reqiiired and the composition of the mash can be chosen in such a manner that the grain which is the cheapest at the time shall predominate in it. With regard to the apparatus used and the space required for fer-mentation the method (1) is the most expensive and suitable only for places where no duty has to be paid on vessels and other apparatus.Regarding the labour attached to the three methods it is shown that methods (1) and (3) reqnire only a very small staff of workmen. Method (2) requires more workmen. The largest yield of yeast is obtained from method (1); most spirit fi-om (2) ; this difference is due to the composition of the mash and can be decreased by mashing less maize and more rye in method (2). The reason why the method (3) gives a low percentage of siiirit is that the extraction of starch from the grain is never effected completely with malt alone but that the process is continued when t.he mash is allowed to ferment with the returns as is the case with methods (1) and (2).In the working of method (3) however. the clear mash is alone employed so that a portion of the starch is not dissolved but remains behind with the returns when sifted. Method (1)gives the finest quality of spirit its purity being due to the absence of' maize whose fatty and oily ingredients give the spirit a bad taste which is difficult to remove. The small yield of yeast in method (3) is due to an analogous cause. The niash obtained from methods (1)and (2) is generally turbid when it is pumped from the fermenting vessel into the boxes. This turbidity is caused by admixtures of albuminous substances finely divided cellular tissues &c. which are probably dissolved during the fermentation and thus increase the yield of yeast.The yeast obtained from method (3)is perfectly white and very pure. The authors experimented on the above-mentioned methods with the view of disco\-ering a new method combining with method (3)all the advantages of the other two methods. The following are the results obtained. In the first place the grain is well trimmed and ground into a fine powder. In order to prepare the mash tu-o-thirds maize and qe and one-third malt are used. After having boiled the maize and rye with steam the mixture is saccharificd with malt and tlie mash pumped into filter-presses. By boiling the former substances with steam before using them it is possible to increase the quantity of rye used and to work with larger quantities of the latter. The advantages which are gained by using filter-presses are that tlie returns require less water for washing purposes and therefore yield a clearer and more con-centrated mash.The returns after pressing are washed with hot water. The clear mash is cooled brought into the fermenting vessel the necessary quantity of wash added and the wliole treated with yeast. By passing filtered air though the mixture a more ready and ABSTRACTS OF CHEMICAL PAPERS. a larger formation of yeast is resulted. During the time allowed for fermentation tlie filter-presses are opened the pressed cakes taken out put into boxes treated with water and boiled with dilute acid in a copper still. The reason why acid is used is that it extracts a larger quantity of product from the returns than water alone.After one hour’s boiling the still is opened and the resulting mash brought into the filter-presses. ‘I’he clear mash is cooled mixed with water and added to the fermentiug mash. After the end of the fermen-tation the clear mash is syphoned off and pumped into retorts where the washings are redistilled while the residual yeast is washcd and pressed. The returns remaining in the press are dried as completely as possible and are then ready for use. The aclvantages of this method are that (1.) All kinds of grain (and probably even potatoes) can be worked up in yarious proportions and the addition of malt can be decreased. (2.) By working the clear concentrated mash the space for fermen-tation is thoroughly utilised. (3.) The shallow cooli~g and fermenting vessels are not rcqnired.(4.) The mash becomes clear without being boiled. (5.) The yield of yeast and spirit is high the yeast pure and white and the spirit from rye of a fine quality. (6.) ‘I’he costs for labour &c. are but slight. (7.) The consumption of coal is small. D. B. Manufacture of Glue. By B. TE KNE (Diwg7. pZyt. J. ccxxi 251-258).-The author contradicts the assertion of Gintl that “the quality of the glue is not impaired by the use of high pressure steam ;” on the contrary he finds that tlie inferiority of the prodnct is directly proportional to the pressure of the employed steam till at length all the gelatin is destroyed. The same material which at a pressure of 10 to 20 lbs. per square inch yields a tolerably good product yields at a pressure of 30 lbs.or orer (duration of boiling being in both cases equal) a perfectly white substance quite innocent of gelatin. The author states that the liquors obtained on steaming the slaughter- house refuses may besides being valuable for glue production be looked upon as a source of ammonia. Seeing that a high temperature is injurious to the gelatin in the extractive liquors to be boiled down the author proposes the use of vacuum-pans for this boiling down pro-cess. It is asserted that a glue factory is no more prejudicial to the health of a neighbourhood tlian a starch or yeast factory. The raw materials used for glne-makii:g in the United States are comprised in two classes-(I) Slaughter-house refuse and remains ; (11) Kefuse of tanneries.The preparation of bone-glue by extraction of the mineral constituents of bones by means of hydrcchloric acid thus leaving the gelatin pays only in those neighbourhoods where hydrochloric acid is to be had cheap. Use qf Blauyhter-house R<fuse.-According to thcir value as a source of glue the varieties of the raw materials are arranged as follows :-(1) Feet of oxen; (2) pig’s feet; (3) feet of calves and sheep; (4) fresh bones; (5) heads of sheep and oxen. The raw material is TECHNICAL CHEMISTRY. freed from blood as much as possible and rednced to as fine a condition of division as practicable the flesh being torn to pieces and the bones broken by a suitable machine and then m-ashed free froin dirt and blood.The matter is then ready for the boiling operation in the ordi- nary course hut the author here introduces a process for bleaching by meaus of sulphurous acid. This is done in wooden vats closely covered and a saturated sulphurous acid solution is used. The time required for the bleaching depends greatly upon the condition of the material. By means of this important process an extractive liquor is obtained nearly as clear as water which by evaporation in the vacuum pan yields a glue unsurpassed for clearness and lustre by tlie very first qualities. The bone-fat is likewise clearer and free from objectionable odour and commands a considerably improved price. In order to pre- pare the concentrated sulphurous acid solution a sulphur-burner from the roof of which a stoneware pipe passes supplies a reservoir with sulphurous oxide gas.This gas afterwards passes up a coke tower (connected with the upper part of the reservoir by a series of short stoneware pipes) and meets a slow current of water which trickles down amongst the coke and is supplied by a cistern from ahore. The result'ing concentrated solution accumulates in the reFervoir below. The action of the acid is very Characteristic. The particles of skin and flesh swell out and finally assume the lustre of silk and the trans- parency of gelatin. The mass is also rendered much more porous and thus can be far more quickly converted into glue. The boiling pro- cess then follows and the advantage of the previous bleacliing is made evident in the short time and low pressure required in this boiling which gives a good concentrated liquor.The melted fat is removed by taps. The liquor free from fat is now passed through a filter con- tairiiiig bone-charcoal but the author believes that a filter-press manufactured by Wegelin aud Hubner of Halle would answer the purpose better. From the filter tlie liquor passes to the vacuum-pan where it is evaporated down till of siicli a consistency that the resulting glue may be easily cut or if cast in moulds easily detached therefrom and in a short time. For the pouring plates of tinned sheet iron are genetdly used but recently glass tables have been introduced by the use of which an extraordinary gloss is conferred upon the glue. These tables are however liable to frequent breakage.When moulds are used they are cooled down by cold water and ice and when the temperature falls to within 0" and 5" the glue niay be removed. A process bas been recently patented for America in which benzene is used for removing the fatty portions of the raw material for glue-making. w. s. Logwood Inks. By E. U. VIEDT(Pharm. J. Trans. [3] vi 1004).-Inks prepared from logwood are of four classes viz. with logwood and chrome with alum with copper or with iron. Runge's ink prepared from logwood with a small quantity of potassium chro- mate is good and cheap easily penetrating the paper ;but on exposure to air it deposits black flakes leaving a colourless liquid above. This may be prevented by the addition of a little sodium carbonate ; the following ink is therefore recommended.Dissolve 15 parts of log- 124 ABSTRACTS OF CHEMICAL PAPERS. wood extract in 900 of water ; leave the liquid to deposit and decant ; heat and add 4 parts of crystallised sodium carbonate; lastly add drop by drop a solution of 1 part of potassinin chromate in 100 of water. Inks prepared from chrome-alum have little depth of colour. Under the influence of air reaction takes place between the metallic salts and the colouring matter ; sulphuric acid is therefore added and this attacks the pens. If metallic salts are used cupric sulphate is preferable. One of the best formulas for this kind of ink is the following given in proportions for a manufacturing scale :-20 kilograms of extract of logwcod are dissolved in 200 litres of water and the solution clari6ecl by subsidence and decantation.A yellowish-brown liquid is t.hns obtained. In another vessel 10 kilograms nf ammonia-alum are dis- solved in 20 litres of boiling water; the two solutions are mixed there being also added 200 grams of sulphuric acid and finally 16 kilogram of sulphate of copper. The ink should be exposed to thc air for a few days to give a good colour after which it shonlcl be stored in well-corked bottles. Boettger gives the following formula :-30 grams of extract of log-wood are dissolved in 250 grams of water; 8 grams of crgstallised carbonate of soda and 30 grams of glycerin of density 1-2.5are added ; and lastly 1 gram of yellow chromate of potassium and 8 grams of gum arabic reduced to a powder arid dissolved in several grains of water.’ This ink does not attack pens does not mould and is very black. E. IV. P. Carbon Disulphide as an Antiseptic. By HUGOSCH~FF (Dezct. Chew,. Ges. Ber. ix 828) .-Cocoons of silkwornis which had been killed by exposure to the vapours of carbon disulphide under- went no change during six months’ keeping in flasks in the laboratory. The bodies of some pigs which had been used for physiological experiments were put into a stoppered vessel with a few c.c’s. of carbon disulphide in 1869 and have been perfectly preserved without decomposition. The same result was obtained with a lizard 35-45 centimeters long which had been suffocated accidentally in 1869 and was bottled whole.In this case a small quantity of liquid collected at the bottom of the vessel and the green hue of tlie skin became a dirty greyish-green but not the slightest putrefaction occiirred. Similar results were obtained with the intestines of poultry im- mersed in water in 1872 with a little carbon disulphide in a bottle with a greased stopper ; with a lump of beef weighiny 200 grams ; and witli the body of a finch killed by paraconine. The bcef yielded a normal flesh fluid and was eaten by a dog without hesitation even after several months. C. R. A. 17.