178 Memoranda on Explosive Cotton* \J?ev. 



dissolved and the solution evaporated spontaneously on a flat surface, 

 affords a transparent, colourless, glass-like paper, exactly the same hi 

 appearance and properties as that which accompanied the specimen of 

 Schoenbein's cotton sent to Calcutta. 



Reserving for a moment the description of the process followed by 

 Mr. Siddons and myself, as soon as a sufficient supply was obtained 

 for analytical experiments, I ascertained that the cotton which in its 

 natural state is a compound of carbon, and the elements of water, had 

 by immersion in a mixture of equal measures of strongest nitric 

 and sulphuric acids, parted with its constituent water, and that in 

 the place of this had been substituted one of the series of Nitrogen 

 and Oxygen compounds. The use of the sulphuric acid is simply 

 by its powerful affinity for water to withdraw this from the carbon 

 of the cotton ; no portion of this acid or its constituents enters into 

 the composition of the new explosive compound. Ultimately the 

 explosive cotton was found to be a compound of Nitrogen, Carbon, and 

 Oxygen, isomeric with (or of being the same ingredients and pro- 

 portions as) the old and well known fulminic or cyanic acid, the active 

 principle of the fulminating silver, mercury, &c. But here as in many 

 other isomeric compounds, numerous differences in properties became 

 manifest, depending chiefly on the mechanical structure of the different 

 forms of the preparation. I have not as yet completed to my own 

 satisfaction a sufficient number of exact analyses to warrant my express- 

 ing the results in figures, but the numerous facts which I have observ- 

 ed, tend to the conclusion that all the isomeric varieties of cyanic acid 

 are represented in the explosive cotton, passing into each other under 

 the influence of slight and often inappreciable circumstances, the general 

 event being the formation of a substance bearing a close resemblance to 

 Cyamelide (C. 2. O. 2 -f- N. H.) being white, neutral, insoluble in water 

 and acids, dissolved in aqua Potassii ammonia being set free, yielding 

 sulphate of ammonia when heated with strong sulphuric acid while car- 

 bonic acid escapes. This description applies equally to Cyamelide and 

 to the best explosive cotton. (See Gregory's Organic Chemistry, 

 p. 295.) 



Without entering upon elaborate chemical details unsuited to the 

 object of this paper, it will suffice to say that we found the prepared cotton 

 to be increased in weight by 20 per 1 00, insoluble in water, unchang 



