American Mineral Nemalite. 389 



siate of potash. By ignition, the mineral assumed a light 

 brownish cast. 



As the quantity of mineral in my possession was small, I 

 could only employ small portions in the analysis. 



To ascertain the amount of the water, 7-51 grains of the 

 mineral were introduced into a weighed tube of German 

 glass, closed at one end. It was then twice bent, and a 

 quantity of fused chloride of calcium introduced into it, the 

 weight of which was ascertained. The open end was then 

 drawn oif, so as to leave a capillary termination, and the 

 closed end strongly ignited, for a quarter of an hour, over a 

 powerful spirit-lamp, with a double draft. The tube was 

 then cut asunder, between the mineral and the collected 

 water, and all the apertures immediately closed with pieces 

 of lute. By the necessary weighings, the loss of weight of 

 the mineral, and the weight of the collected water, were as- 

 certained. The water collected amounted to 27'96 per cent, 

 and the loss of the mineral to 32-62 per cent., the difference 

 being carbonic acid. This would only have given 4*66 per 

 cent, of carbonic acid ; but the following experiments shewed 

 that the heat had not been sufficient nor long enough con- 

 tinued to drive off all the carbonic acid. 



Five grains of the mineral were treated with diluted muri- 

 atic acid in a little bottle having a tube containing chloride 

 of calcium connected with it, to retain moisture. The loss of 

 weight, from escaping carbonic acid, was ten per cent. 



2*43 grains of the mineral were ignited during an hour in 

 a small open platinum crucible. The loss of weight was 39*27 

 per cent. The ignition was continued for a quarter of an 

 hour longer, but no farther loss of weight ensued. This 

 result shews, that the estimate of 27*96 per cent, of water, 

 and ten per cent, of carbonic acid, is not far from the trutli. 

 If the carbonic acid were computed as the difference between 

 the quantity of water and the total loss by ignition, it would 

 amount to 11*31 per cent. 



To ascertain the proportions of the other constituents, the 

 before-mentioned solution of five grains of the mineral was 

 employed. Ammonia threw down a precipitate which, by 

 solution in acid, left 003 of silica, in which was included 



VOL. LXI. NO. LXXXII.— OCTOBER 1846. 2 C 



