108 On the properties and uses of Gun-cotton. 



and dried, was found to be entirely changed in its physical and 

 chemical properties. It was tough, and had somewhat the character 

 of parchment. When heat was applied to it, it burnt rapidly, and 

 was entirely consumed. If these substances were heated with nitric 

 acid, they became dissolved, forming a mucilaginous solution : on 

 adding water to the solution, a white pulpy matter separated, to 

 which Braconnot gave the name of ocyloidine, to signify its derivation 

 from woolly fibre. Subsequently the properties of xyloidine were 

 examined by other chemists. Pelouze confirmed the results obtained 

 by Braconnot, and determined that the new compound inflamed at a 

 temperature below that required for the singeing of paper; i. e. 

 under 400°. He suggested that the material thus prepared might be 

 made useful for certain purposes in the artillery, but without stating 

 how or in what way he proposed to apply it. 



The subject attracted no further notice, until, in the course of the 

 last summer, Professor Schonbein announced to the British Associ- 

 ation that he had succeeded in procuring from cotton- wool a very 

 explosive substance, which might be made a useful substitute for 

 gunpowder : to this he gave the name of Gun-cotton. For some 

 time before this announcement, he had been engaged in researches 

 which had led to the discovery of a singular principle called ozone, 

 one of the most powerful oxidizers with which we are acquainted ; 

 and it is probable that these researches led to his perfecting the pro- 

 cess, the first foundation of which had been laid by Braconnot, 

 Schonbein ascertained that the inflammable compound of cotton was 

 produced in a much more perfect degree by the mixture of sulphuric 

 with nitric acid than by nitric acid alone ; and the proportions which 

 he employs are, two parts by measure of sulphuric with one part by 

 measure of nitric acid, both of the acids being in their most concen- 

 trated state.* Professor Brande having mixed the acids in these pro- 

 portions, the mixture formed a colourless liquid of a high temperature, 

 and evolved copious acid fumes. He then observed that it was pro- 

 bable that some new substance (ozone ?) was here produced, since the 

 two acids thus mixed had properties entirely different from those 

 possessed by either separately. Thus neither nitric nor sulphuric 



* We observe that Schonbein in his patent specifies three parts of sul- 

 phuric acid to one of nitric. — Ed. 



