288 Mr. Ahel on Chemistry for Military Purposes. [May 23, 



The most important of these materials for producing coloured 

 fires were stated to be the oxide and sulphide of copper, and the 

 chlorate of copper and potassa; the nitrate of lead, the sulphide of 

 arsenic (orpiment) ; the sulphide of mercury (Ethiops mineral), and 

 the sub-chloride (calomel) ; zinc, antimony, and iron, as metals, in 

 the state of filings, &c. ; the carbonate, nitrate, and chlorate of 

 baryta ; and the carbonate and nitrate of strontia. Chlorate of 

 potassa was largely employed to increase the vehemence of the 

 combustion of many compositions containing colouring substances, 

 whereby the brilliancy of the resulting tints is much heightened. 

 The chlorate of baryta had lately been prepared on a very large 

 scale for pyrotechnic compositions, and large specimens of this very 

 beautiful salt were exhibited. In endeavouring to prepare a com- 

 pound of the chlorate of copper with ammonia (similar to the 

 so-called ammonio-nitrate of copper), as a material for a brilliant 

 purple fire, Mr. Nicholson had obtained a beautifully crystalline 

 compound, of so powerfully explosive a character, that even its 

 syrupy solution detonated sharply when struck with a hammer upon 

 an anvil. The substance in question was more dangerous to ma- 

 nipulate with than fulminate of mercury, but it underwent gradual 

 decomposition on exposure to air, accompanied by a diminution 

 of its explosive properties. Some experiments in connection with 

 this compound had led to the observation that the ammonio-nitrate 

 of copper, when thoroughly dry, also possessed slight detonating 

 properties. 



Mr. Abel concluded his discourse by expressing the hope that 

 he had succeeded in laying before his audience some interesting 

 proofs of the intimate connection of chemical with military science, 

 and of the successful practical applications of the results of scientific 

 research to purposes, which have proved so recently, to possess the 

 highest national importance. 



[F. A. A.] 



