Intelligence and Miscellaneous Articles. 299 



Carbon 59-84 59-77 60-07 



Hydrogen 8-73 8-80 9-20 



Azote 4-11 4-83 



Sulphur 3-78 3-89 



Oxygen 16-45 16-32 



Soda 7-09 6-89 



100-00 100-00 



Journ. de Pharm. et de Ch., Fevrier 1847. 



SINGULAR PROPERTY OF GUN-COTTON MIXTURE. 



Dr. Draper has made the following observations : — Lecturers on 

 chemistry have known for a long time, that one of the best methods 

 of illustrating the properties of carbonic acid gas, is to evolve it from 

 carbonate of ammonia by the action of monohydrated nitric acid. 

 A dense white fume accompanies the gas, and marks all its move- 

 ments in a striking manner. 



Commercial nitric acid fails to produce the same eflfect. It sets 

 the gas free in an invisible state. But if a mixture of commercial 

 nitric acid and oil of vitriol be used, then the dense fume is at once 

 produced. The explanation seems to be, that the oil of vitriol, by 

 retaining water, allows some of the carbonate of ammonia to pass 

 off with the carbonic acid in a dry state, and hence gives the gas a 

 smoky aspect. 



But it is singular, that though oil of vitriol will of course decom- 

 pose carbonate of ammonia very rapidly, the gas which escapes is 

 transparent. 



Some months ago Dr. Ellet, of South Carolina College, published 

 a process for preparing gun-cotton, which is unquestionably the 

 greatest improvement yet made in the preparation of that explosive 

 substance. His plan is to soak cotton in a mixture of oil of vitriol 

 and saltpetre, and then wash it thoroughly from the adhering salt. 

 Now if this mixture of oil of vitriol and saltpetre be made to act on 

 carbonate of ammonia, like monohydrated nitric acid, or common 

 nitric acid mixed with sulphuric, it evolves carbonic acid in the 

 smoky state. 



ON THE DEHYDRATION OF SULPHATE OF LIME UNDER VARIOUS 

 CIRCUMSTANCES. BY M. M. E. MILLON. 



The author observes that it is well-known that sulphate of Ume 

 which is slowly produced, retains its water of combination at a tem- 

 perature at which precipitated sulpliate loses it. 



Sulphate of lime. — Tliis salt contains two equivalents of water. 

 S0^ HO-)-CaO, 110 ; according to Graham it suifers no loss at 

 212'-' F., and becomes anhydrous at 266°. The general results ob- 

 tained by M. MiUon effect considerable changes in this statement. 



Sulphate of lime, of whatever form, origin or mode of formation, 

 always suffered a first loss, varying from 15 to 17 per cent. Tliis 

 quantity represents 1-5 equivalent of water : its eliminatiou is per- 



