38 PROCEEDINGS OF THE 



periments have been made, especially by the French ; but such Berioue difficulties 

 presented themselves that the idea seemed abandoned in every country but one, 

 Austria. From time to time accounts reached England of its partial adoption in 

 the Austrian service, though no explanation was afforded of the mode in -which 

 the difficulties had been overcome, or the extent to which the attempts had been 

 successful. The Committe, however, had been put in possession of the fullest 

 information from two sources — Prof. Abel, chemist to the War Department, and 

 Baron W. von Lenk, Major-General in the Austrian Artillery, the inventor of the 

 system. Prof. Abel, by permission of the authorities, communicated to the Com- 

 mittee the information given by the Austrian Government to our Government, and 

 also the results of his own elaborate experiments. General von Lenk, on the invi- 

 tation of the Committee, by permission of the Austrian Government, paid a visit 

 to this country, to give every information in his power on the subject, and brought 

 over drawings and samples from the Imperial factory. The following is a sum- 

 mary of the more important points: — As to the chemical nature of the material, 

 Von Lenk's gun-cotton differs from the gun-cotton generally made, in its complete 

 conversion into a uniform chemical compound. It is well known to chemists that, 

 when cotton is treated with mixtures of strong nitric and sulphuric acids, com- 

 pounds may be obtained varying considerably in composition, though they all 

 contain elements of the nitric acid and are all explosive. The most complete 

 combination (or product of substitution) is that described by M. Hadon as Cgg 

 Hjj (9 NO^^) O30, which is identical with that termed by the Austrian chemists 

 Trinitrocellulose, Cj^ H, (3 'SO^) Oj^, This is of no use whatever for the mak- 

 ing of collodion ; but it is Von Lenks's gun-cotton, and he secures its production 

 by several precautions, of which the most important are the cleansing and perfect 

 desiccation of the cotton as a preliminary to its immersion in the acids, — the em- 

 ployment of the strongest acids attainable in commerce, — the steeping of the 

 cotton in a fresh strong mixture of the acids after its first immersion and consequent 

 imperfect conversion into gun-cotton, — the continuance of this steeping for forty- 

 eight hours. Equally necessary is the thorough purification of the gun-cotton so 

 produced from every trace of free acid. This is secured exclusively by its being 

 washed in a stream of water for several weeks. These prolonged processes are 

 absolutely necessary. It seems mainly from the want of these precautions that 

 the French were not successful. From the evidence before the Committee it ap- 

 pears that this nitric compound, when thoroughly free from acid, is not liable to 

 some of the objections which have been urged against that compound usually ex- 

 perimented upon as gun-cotton. It seems to have a marked advantage in stability 

 over all other forms of gun-cotton that have been proposed. It has been kept un- 

 altered for fifteen years; it does not become ignited till raised to a temperature 

 of 136*^ C. (277° Fahr.); it is but slightly hygroscopic, and when exploded in a 

 confined space, it is almost entirely free from ash. There is one part of the pro- 

 cess not yet alluded to, and the value of which is more open to doubt — the treat- 

 ment of the gun-cotton with a solution of silicate of potash commonly called water- 

 glass. Prof. Abel and the Austrian chemists think lightly of it ; but Von-Lenk 

 considers that the amount of silica set free on the cotton by the carbonic acid of 

 the atmosphere is really of service in retarding the combustion. He adds, that 

 some of the gun-cotton made at the Imperial factory has not been silicated at all^ 



