96 



CHEMISTRY. 



it can be consumed. The quality should there- 

 fore be closely watched, and as soon as a par- 

 ed is found to be strongly acid it should be 

 rejected. The test of acidity, by means of a 

 glasa rod, wet with solution of ammonia, held 

 mar tlu- mouth of the bottle, though useful, is 

 not entirely trustworthy, and is hypercritical, 

 >ince the vapor of anhydrous chloral, whether 

 of itself or by slight decomposition from air 

 contact, produces a cloud with ammonia. 



Artificial Butter. The Victualling Depart- 

 ment of the French Navy some time ago 

 caused experiments to be made upon the arti- 

 ficial production of butter, as a substitute for 

 the real article, which easily becomes rancid. 

 It was observed that cows, kept on a very 

 scanty diet, continued to give milk, although 

 in very much smaller quantity, and that such 

 milk always contained butter; this suggested 

 that the butter was due to the absorption of 

 the fat contained in the animal tissues, which 

 was converted into butter under the influence 

 of the milk-secreting glands. This led to ex- 

 periments on the splitting up of animal fats, 

 and further, to the following process for mak- 

 ing butter artificially : Best fresh beef-suet is 

 first mechanically cut up, by means of circular 

 saws fitted to a cylinder, and is next placed in 

 a vessel containing water, carbonate of potas- 

 ea, and fresh sheep's stomachs previously cut 

 up into small fragments; the temperature of 

 this mixture having been raised to 45, the 

 joint influence of the pepsine of the stomachs 

 and heat causes the fat to be separated from 

 the cellular tissue: the fatty matter floating 

 on the top is decanted, and, after cooling, sub- 

 mitted to very powerful hydraulic pressure; 

 the stearine is used in candle-making, and the 

 serai-fluid oleomargarine is used for making 

 the artificial butter in the following manner : 

 50 kilos, of the fat are poured, along with 25 

 litres of ,milk and 20 litres of water, into a 

 churn, while there are added 100 grms. of the 

 soluble matter obtained by soaking for some 

 hours in milk from cows' udders and milk- 

 glands; a small quantity of annatto is also 

 added, and the operation of churning then pro- 

 ceeded with. The butter thus obtained is 

 well washed with cold water, and, if required 

 to be kept for a long time, melted by a gentle 

 heat, to eliminate all the water. According to 

 reports of sanitary committees, as well as of 

 the authorities of the Victualling Department 

 of the French Navy, this artificial butter is 

 really an excellent substitute for genuine but- 

 ter, and can be exposed for sale if the vessels 

 are marked to distinguish the artificial from 

 the genuine butter. 



New Method of obtaining Potassium. The 

 American Chemist prints a note from Prof. A. 

 E. Dolbear, relative to a new and convenient 

 mode of obtaining potassium, which had hith- 

 erto only been procurable by the reduction of 

 the carbonate of potash mixed with charcoal, 

 heated to a high degree, in iron retorts. Prof. 

 Dolbear dissolved some white stick caustic 



potash of commerce in water^ and treated it 

 with sulphuretted hydrogen in the way adopted 

 for making potassium-sulphide. The solution 

 was evaporated until it was solid when cool, 

 when the yellowish mass was mixed with more 

 than its bulk of iron filings and chips, and the 

 whole put into an alembic for distillation. 

 The heat of a furnace was applied till the 

 alembic was of a bright red heat, and the prod- 

 ucts of distillation were received in common 

 coal-oil. The product was rather small, as 

 some of the potassium-vapor decomposed the 

 heated vessel; nevertheless the potassium 

 showed itself, when the oil was poured off and 

 the residuum turned upon water, by its charac- 

 istic ignition and flame. The reaction is sim- 

 ple, and may be thus represented: K 2 S+Fe= 

 FeS+K 2 . 



He did not have conveniences for experi- 

 menting upon this on a scale large enough to 

 test its comparative value ; it needs some spe- 

 cial arrangements of protected Vessels, as it 

 violently attacks common crucibles, porcelain, 

 and glass. The materials used for thus ob- 

 taining it are of the required cheapness, and 

 the iron sulphide product can again be used to 

 furnish sulphuretted hydrogen for another 

 quantity. The author thinks it probable that so- 

 dium can be obtained by an analogous process. 



Researches on Alcoholic Fermentation. The 

 eminent French chemist, Prof. J. Dumas, lays 

 down the following laws of Nature in the pro- 

 cess of alcoholic fermentation, as observed by 

 himself: " No chemical movement excited in a 

 saccharine liquor can convert sugar into alco- 

 hol and carbonic acid ; the simple fermenta- 

 tion of a-saccharine liquor and yeast may be 

 regulated like any other chemical reaction ; 

 the duration of the fermentation is exactly 

 proportionate to the quantity of sugar con- 

 tained in the liquid ; fermentation proceeds 

 more slowly in the dark and in vacuo ; no 

 oxidation takes place during the fermentation ; 

 sulphur is converted into sulphuretted hydro- 

 gen by the fermentation ; neutral gases do' not 

 modify the fermentation -inducing action of 

 yeast; acids, bases, and salts, can exercise an 

 accelerating or retarding, disturbing or de- 

 structive, action on fermentation, but the ac- 

 celerating action is more rarely observed ; very 

 dilute acids do not affect fermentation, but I 

 acids in larger quantity completely destroy it ; 

 the same applies to alkalies; carbonated alka- 

 lies only impede fermentation when they are 

 present in, or added to, the fermenting liquid 

 in large quantity; earthy carbonates do not 

 interfere with fermentation ; neutral salts of 

 potassa and of some other bases exert no in- 

 fluence upon the process ; silicate of potassa, 

 borate of soda, soap, sulphites, hyposulphites, 

 neutral tartrate of potassa, and acetate of po- 

 tassa, may be applied for the physiological 

 analysis of ferment and for studying its mode 

 of action." 



Distillation ~by Cold. This is the name of a 

 process by which the author, Mr. D. H. Smee, 



