ABSTRACTS OF CHEMICAL PAPERS. Technical Chemistry. Prepamtiom of Hydrogen Gas.* THE Journal of the Society of Arts states that M.M. Tessi6 du Motay and Marechal have lately discovered a new and economical method of producing hydrogen gas. The process consists in heating the hydrates of the alkalies and alkaline earths with coke coal charcoal &c. to a red heat whereupon carbonic acid and hydrogen are given off abundantly ; and as the decomposed hydrates especially that of lime can be used indefinitely by simply remoistening them with water the method is very economical. In this operation the hydrogen gas is generated without any special production of steam and may thus be produced without any other generating apparatus than the retorts themselves ; and as these retorts are not exposed to the direct action of the steam they are not subject to any interior deterioration.This process it is said in conjunction with the method of obtaining cheap oxygen from the manganates of soda discovered by the same chemists is likely to create a revolution in many industries and especially in metallurgy. 3. B. On the Application of certaiw Fluorine-compounds for the Preparation of Frosted @lassfor Photographic Purposes. By E. S I E Gw ART.? IN place of aqueous hydrofluoric acid for etching glass the author recommends a solution of eight parts of an alkaline fluoride dissolved in 100 of water and mixed just before using with one part oil of vitriol. Before immersion in this bath the glass requires to be cleaned in another made with potassium dichromate and sulphuric acid to remove all traces of organic matter from its surface.A few hours at ordinary temperatures suffice to produce a fine glistening frost. The reat of the paper contains details concerning the preparation and use of etching-wax for producing patterns and figures. C. H. G. On the Constitution of Ultmrnarine. By W. STEIN. DOESultramarine as a whole constitute a chemical compound and in what state of combination does the sulphur exist therein ? Examining the latter point the author rejects the idea of the sulphur * Pharm. Trans. [S] I 566. t Dingl. Polyt. J. csix 222. $ Journ. pr. Chem. [23 iii 39. TECHNICAL CHEMISTRY. 167 existing either as hyposulphite sulphide or polysulpliide of sodium and while admitting the presence of sodic sulphite in most samples of ultra-marine considers its presence accidental the essential sulphur consti- tuent being aluminium sulphide.He finds that aluminium sulphide exists in two forms as a crystalline colourless (yellow) mass and as an amorphous black powder. The black modification arises when the body is formed at comparatively low temperatures or when the presence of foreign matter between the particles prevents them fusing together. He considers that this last condition obtains in the ultramarine manu- facture and that the characteristic blue colour of the body is due not to its chemical composition but to its mechanical structure-that it owes its colour indeed to the same causes which give a blue tint to a mixture of lamp-black and milk &c.He therefore concludes that ultramarine (blue) consists of a white (ground) mass with which black aluminium sulphide is mingled in a state of molecular division. White ultramarine he regards as the blue compound the colour of which is compensated by the orange-red of sodium sulphide present with it and the green pigment as arising from the conversion (partial ?) of the orange-red sodium sulphide into sodium bisulphide whereby yellow and blue occurring together give rise to green. C. H. G. The Efects of Cold Zcyon t7~eStrength of Ivon. By W. BROCKRANK.* THE bars of pig-iron employed were made from a mixture of four pig- irons of the highest class added to some good scrap-iron so as to insure a sounder and more regular casting; all the bars were cast from one ladle.The testing machine used was a powerful lever or st,eel-yard the bars having a three-foot bearing. The results showed a gradual and considerable decrease of strength in the bars with the in- crease of cold below the freezing point. They also lost their elasticity in a similar degree. Tension. Tension. .-'P At 20'. At 80". /At 20". At 80". ' 2142 lbs. 2142 lbs. 16$ twists. 1G twists. 2114 , 2058 , 15.& , 14i 99 2114 , 2086 , 9 ,? 13Q 9 a 9, 2142 , 2086 , 14 ?> 144 2114 , 2128 , 16 , 124 9 2114 , 2086 , IS!? ,9 Wi 99 -Total.. 12640 , 12586 , -90 9 834 , $7 Average 2123.3 2097.6 15 13.9 ,) * Chem. News xxiii 62. 168 ABSTRACTS OF CHEMIOAL PAPERS.Mr. Brockbank refers to the general experience of ironfounderq and cites instances of breakages of castings during frosty weather showing that the strength of cast iron is very materially lessened by severe cold. Experiments were also made to test the effect of frost upon the tensile strength of wrought iron. The methods used by Kirkaldy viz. torsion and gradual tensile strain did not give a true result as the iron tested worse when warm than when frozen. The simple test of the striker's hammer was then resorted to and a number of experiments was described showing "short ') crystalline fracture in the iron without any appearance of fibre whilst the same iron,-a strip of boiler plate,-after being slightly.warmed to " dispel the frost," was exceedingly tough and fibrous showing a good fibrous fracture.Rails in course of manufacture for East Indian railways at the Dar-lington Iron Company's Works failed to pass the required test in frosty weather whereas at ordinary temperatures a failure was a very rare occurrence. Rails were heated to 120" F. others were tested at the temperature of 26" F. The following table shows the results :-Test of East Indian Railway Rails,82 lbs. per yard November 29 1869 tested by a Falli.iLg Weight of 2,000 lbs.; Cewhes of Support 3 feet 6 inches apart. Number of Height Permanent Tempera-Remarks. blows. of falls. set. ture. ft. in. Firat blow.. .. 50 7-16th .. Second , . . .. 50 3-4th~. . .. 120" Not broken. Third , .... 70 *.*.1 5 0 13-lGth~ .. 1 Do. Ditto. First )) .. . . 50 3-8th~... . Second ,) .... Third 70 .,.. ) ,... .. .. ,) First 50 34th~.. . . Second , ,... 50 13-16ths .. Do. Ditto. Third ,) .... 70 .. .. First ,) ,... 50 34th~.,. Second , .... 50 743th~..,. Do Ditto. Third , .... 70 .. .. First , . . .. 50 Second , .... 50 .... 26" Broke with 2nd blow. First , .... 50 3-8ths.. , Do. Passed test. Second , .. .. 50 5-8th~.. . . } First , .... 50 Second , .... 50 ..t. Do. Broke with 2nd blow. First .... 50 Second , .... 50 Do. Ditto. First , ,... 50 Broke .. . Do. Broke with 1st blow. First ) ,... 50 Do. Broke with 2nd blow. Second ,) .... 60 TECHNICAL CHEMISTRY. All the experiments adduced prove that iron becomes much weaker both in its cast and wrought state under the influence of low tempera- tures.It loses its toughness becomes quite brittle under sudden impact and changes its structure &om fibrous to crystalline. W.V. On the Production of Alloys of Iron and Manganese and on their Appli-cation to the JIawufactzcre of Steel. By P. ROIIN.* THEauthor after referring to Heath’s patent in 1839 for the employ- ment of manganese in the manufacture of steel and to the use of late years of the Spiegeleisen of Rhenish Prussia and other ferro- manganese alloys in the Bessemer Siemens-Martin and other pro- cesses proceeds to describe the process of Henderson of Glasgow. This process which has been at work for some time at the Phamix Foundry Glasgow consists in reducing upon the open hearth of a Siemens’ furnace a mixture of carbonate of manganese and oxide of iron in presence of excess of carbon by means of st neutral or reducing flame.The furnace bottom is of ground coke consolidated and baked up to form a crucible on a large scale. The charge of finely ground oxides mixed with powdered charcoal or coke is heated to redness for several hours. It thus becomes converted into a metallic sponge which contains the reduced metals from both oxides and is then run down to a regulus by raising the temperature to a full white heat. The quantity of manganese in the alloy depends chiefly upon the high temperature obtained at this latter stage of the process hence the necessity of employing a Siemens’ furnace by which a high reducing tempera- ture can readily be obtained.Though considerable loss occurs owing to the action of the silica in the ores used upon the manganese yet with proper selection of mate-rials an average of 20 per cent. to 30 per cent. of manganese is obtained in the alloy. An ordinary-sized furnace worked by one man can produce 15 cwt. of ferro-manganese every 24 hours. The cost by this process the author states to be about S7 perton for alloy containing 20 to 25 per cent. of manganese ; this is exclusive of royalties the amount of which per ton the author does not state. The author concludes by pointing out, that not only will the manufacture of these ferro-manganese alloys prove a profitable accessory to every Bessemer steel works in the country but that it will also make these works independent of the fluctuations and uncertainties of the foreign SUDDlY.C. G. * Journal of the Iron and Eltee1 Institute Feb. 1871,70. ABSTRACTS OF CHEMICAL PAPERS. Ohserrations on the Manufacture of Vermilion. By M. ALs BE EG.* IN manufacturing vermilion by Martin's process two stages are to be observed first the formation of the amorphous black sulphide and second the conversion of this into the crystalline red modification by the successive solution of the black sulphide by the alkaline sulphide present and its deposition in the red form. The crystals of red sul- phide so obtained are rhombohedrons approaching a cube. They are doubtless the primitive rhombohedrons observed on the native crystals R on R 92" 36'.The solubility of sulphide of mercury in alkaline sulphides constitutes a source of loss of from 5 to 8 per cent. of the mercury employed in this process. C. H. G. Black Lz1sti.e Colozhr for Sthgchr-paper. 'By Dr. KIELMEYl3R.t 8 lbs. ordinary glue 16 lbs. water 1lb. potato starch 5& lbs. water 521bs. Campechy extract of 6" Baume 1lb. 2 oz. green vitriol 8%lbs. brown glycerin ; all boiled together and stirred when cold. Paper once painted with this mixture acquires when dry a fine bright black surface remains supple and does not exhibit a tendency to get sticky. If it be desired to render the paint thicker or thinner the starch and the glue must be increased or diminished in the same proportion or the lustre will be spoiled.C. H. G. ('Sucrnte of Hydrocurbo?zate of Liwe " applied to the purijication of flugar-cnne Juice. By BOWINand LOISEAU (Chem. News xxiii 19). Preparcrtion of yzLic32ly-7~a?.deizi72Ycolauyecl Cements. By R BOETTGER. WHENfinely-pulverized chalk is stirred into a solution of soda-water glass of 33" B. until the mixture becomes thick and plastic a cement is obtained which will harden in between six and eight'hours possessing an extraordinary durabi:ity and alike applicable for domestic and industrial purposes. If any of the following substances be employed besides chalk diffcrently-coloured cements of the same general character are obtained. 1. Finely pulverized or better still levigated stibnite (grey antimony or blnck sulphide of antimony) will produce a dark cement which after buroishing with an agate will present a metallic appearance.* Chein. Kcws xsxiii 73. t Dingl. Polyt. J. cscix 233. 1 Pharin J. Trans. [2] iii 19. TECHNICAL CREMIXTRY. 171 2. Pulverized cast-iron a grey cement. 3. Zinc-dust (so-called zinc-grey) an exceedingly hard grey cement which after burnishing will exhibit the white and brilliant appearance of metallic zinc. This cement may be employed with advantage in mend-ing ornaments and vessels of zinc sticking alike well to metals stone and wood. 4. Carbonate of copper a light green cement. 5. Sesquioxide of chromium a dark green cement. 6. Thenard’s blue (cobalt blue) a blue cement.7. Minium an orange-coloured cement. 8. Vermilion a splendid red cement. 9. Carmine-red a violet cement. On a curious property of Gun-cotton. By L. BLECKRODE.~ A FLAME may be applied to gun-cotton which has been previously wett,ed with carbon bisulphide without explosion taking place Only the latter substance takes fire immediately the gun-cotton remaining apparently intact amidst the burning bisulphide presenting almost the aspect of a mass of snow slowly melting away. Ether alcohol and benzol may be employed with the game result. The author considers this slow corn- bustion which takes place when the cotton is moistened with carbon bi- sulphide or any other volatile liquid to be a most direct and satisfactory proof in favour of the conclusion to which Professor Abel was led by his researches viz.that if the gases resulting from the first action of heat on gun-cotton upon its ignition in open air are impeded from completely enveloping the burning extremity of the gun-cotton twist their ignition is prevented ; and as it is the comparatively high temperature produced by their combustion which effects the rapid combustion of the gun-cotton the momentary extinction of the gases and the continuous extraction of heat by them as they escape from the point of corn- bustion renders it impossible for the cotton to continue to burn other- wise than in a slow and imperfect manner undergoing a transformation similar in character to destructive distillation. A piece of phos-phorus placed in the moistened mass of gun-cotton is melted and even boils during the combustion but does not burn as it is pre-vented from contact with the oxygen till all the gun-cotton has disap- peared.He suggests that gun-cotton should be preserved under carbon disulphide or benzol by which the danger in case of fire is eliminated. Should the liquid become ignited the cotton will be only slowly destroyed. H. E. A. Phil. Mag. [4],xvi 39. ABSTRACTS OP CHEMICAL PAPERS. Om the recovery of Ta~fctr~c and Oxalic Acids from the Residues of the Lb Discharge ” Process and on Eau de Labarrape as a substitute for Chloride of Lime in dischargi?zg Turkey Red. By ARMAND Mu LLER.~ WHENcloth which is in parts impregnated with one or both of the above-named acids is passed through the discharge vat which con-tains chloride of lime with a greater or lesser excess of lime a well- known decomposition takes place and the acids are converted into their calcium salts which being insoluble settle together with the excess of undissolved lime at the bottom of the vat.If the slimy deposit so prodriced be allowed to remain in the working vat for some weeks with frequent agitation it becomes continually richer in the salts and poorer in free lime till it attains even such it percentage of the former as 65.5 per cent. calcium tartrate and 18 per cent. calcium oxalate. From this mixture washed and somewhat diluted with water the acids are liberated by addition of a previously determined quantity of sulphuric acid of 1.568 sp.gr.,and after stirring and boiling with as much more water as is equal to the weight of the original deposit the liquid is separated from the calcium sulphate by help of a centrifugal machine. Any excess of sulphuric acid contained in the liquid is removed by boiling with barium tartrate. This method is still better when chloride of soda (eau de Labarraque) is employed in the discharging vat in place of the chloride of lime As the tartrate of soda remains in solutioii it is only necessary to add from time to time a sufficient quantity of chloride of lime solution to precipitate all the tartaric acid as a lime salt and to restore the original working strength of the vat. In this case the precipitate will contain no calcium hydrate or carbonate and consequently a great saving of sulphuric acid will be effected. A further advantage is found to follow the use of the soda solution namely that the whites are whiter and the reds are less injured than when the chloride of lime is employed. C. H. G. * Chem. Centr. 1871 134.