Chemistry. 373 



are sufficient for distinguishing the Gay-Lussite from the carbonate of lime ■ 

 and besides these M. Boussingault mentions the two following. 



1. On placing a fragment of the mineral in a watch-glass, and letting a 

 few drops of a solution of oxalic acid fall upon it, a slow effervescence takes 

 place, and, after a few hours, a white powder forms, covered with minute 

 crystals, which it is easy to recognise as the oxalate of soda. 



2. The Gay-Lussite dissolves with brisk effervescence in nitric acid ; 

 and if the solution, when complete, is allowed to evaporate spontaneously, 

 fine crystals of the nitrate of soda are always obtained, swimming in a solu- 

 tion of the nitrate of lime. 



These and other experiments having satisfied M. Boussingault that the 

 mineral of Lagunilla contained lime, soda, carbonic acid, and water, he 

 next proceeded to the analysis. The quantity of carbonic acid was deter- 

 mined by the loss of weight which the mineral experienced when put into 

 dilute nitric acid. The solution, so formed, was evaporated to dryness, 

 the residue taken up by water, and the lime precipitated by carbonate of 

 ammonia at a boiling temperature. The filtered solution was then evapo- 

 rated and ignited to expel the salts of ammonia, and the soda was con- 

 verted in the usual manner into sulphate of soda. The weight of the car- 

 bonic acid, lime, and soda, subtracted from the weight of the mineral which 

 was employed, gave the quantity of water. This estimate was controlled 

 by heating some of the crystals to a commencing read heat, when the wa- 

 ter of crystallization was entirely expelled without any loss of carbonic acid. 

 According to this analysis, the Gay-Lussite is composed (omitting one per 

 cent- of alumina, the presence of which is obviously accidental,) of 

 Carbonic acid, - 28.66 



Soda, - 20.44 



Lime, - 17.70 



Water, .... 32-20 



or, giving to each of the bases sufficient carbonic acid for combining with 

 them, of 



Carbonate of soda, - - 33.96 



Carbonate of lime, 3 L.39 



Water, - 32.20 



Carbonic acid, - 01.45 



M. Boussingault infers from these numbers, that the mineral of Lagu- 

 nilla is a double carbonate of soda and lime, with eleven atoms of water of 

 crystallization ; or, since the crystallized carbonate of soda is composed of 

 one atom of the anhydrous carbonate of soda, with eleven atoms of water, 

 that it may be considered as a compound of one atom of carbonate of lime, 

 combined with one atom of crystallized carbonate of soda. On this view 

 M. Boussingault calculates the composition of the mineral to be 

 Carbonate of soda, - - 34.76 



Carbonate of lime, - - - 32.95 



Water, .... 32.29 



(Extracted from the Annates de Cltimie el tie Physique, (vol. xxxi. 

 25. On Fecula and the different Anu/laceout Substances of Commerce. 



