Carbonate of Magnesia in Calculi. 109 



colour, which excess of ammonia occasions. Lastly, the oxide of 

 antimony, when its solution in an acid is mixed with the tartaric, re- 

 sists both alkalis, and the mostcopious dilution with Avater. In this 

 way oxide of bismuth may be separated from oxide of antimony ; 

 for the former is still precipitable though dissolved in company 

 with tartaric acid. The muriate of platinum is not altered in this 

 respect by tartaric acid ; nor are the oxides of silver, zinc, and 

 uranium. Phosphoric and arsenic acids alone shew some analogy in 

 these properties to tartaric acid. — Gilbert's Annalen, lxxiii. p. 74. 



9. On the existence of Carbonate of Magnesia in the Urinary Cal- 



culi of Herbivorous Animals. By Mr. J. L. Lassaigne. 

 MM. Wurzer, J. F. John, Stromeyer, and Chevreul, had no- 

 ticed this as a constituent of these concretions, in the horse and 

 the cow. M. Lassaigne examined the collection of these calculi 

 in the cabinet of the Koyal School of Alfort. He treated them with 

 sulphuric acid, calcined the saline mass thus obtained, which is 

 principally sulphate of lime, washed it with 3 or 4 times its weight 

 of cold water, precipitated the aqueous solution with bi-carbonate 

 of potash, filtered the liquor, and then exposed it to the action of 

 heat, when he observed the presence of magnesia. Its quantity 

 is indeed small, not exceeding one hundredth and a half, or two 

 hundredths of the weight of the calculus ; but he conceives, 

 however, that carbonate of magnesia always accompanies the car- 

 bonate of lime in such cases. — Ann. de Chim. xxii. 440. 



10. New Process for extracting Elaine from Oils. By M. Peclet. 

 This process is founded on the property which stearine pos- 

 sesses, of saponifying in the cold with strong leys, which does 

 not belong to elai'ne. To separate these two substances, a con-* 

 centrated solution of caustic soda is to be poured upon the oil, the 

 mixture is to be agitated, and gently heated, so as to separate 

 the elai'ne from the soap of the stearine ; after which it is to be 

 passed through a linen cloth, and the elai'ne may be removed from 

 the excess of alkaline solution by decantation. The process 

 always succeeded with all oils, except the rancid ones, or such 

 as had been altered by the heat. The ela'me, obtained by this pro- 

 cess, is perfectly identical with that procured by the processes of 

 MM. Chevreul and Robiquet. 



1 1 . Memoir on the Causes of the Diversities found in Soaps, in re- 

 ference to their hardness and smell; and on a ncto group of 



Organic Acids. By M. Chevreul. 



Hard soaps lose the greater part of their water of fabrication on 

 exposure to air; and when they have lost it, they dissolve 

 slowly and imperfectly in cold water. Soft soaps, on the contrary, 



