MECHANICS AND USEFUL ARTS. 47 



IMPROVEMENTS IN THE SCONCE OF WAR. 



In accordance with the plan pursued during the last two years, we 

 give under the above head a summary of such inventions, discoveries, 

 and applications relative to the science of war, brought before the pub- 

 lic during the past year, as have seemed to the editor as most worthy of 

 notice. 



IMPROVEMENTS IN GUN-COTTON. 



At the British Association meetings of 1862, a joint committee of 

 chemists and physicists was appointed to inquire into and report on 

 the so-called "Austrian Gun-Cotton" At the last meeting of the 

 Association, a chemical report was submitted by Dr. Gladstone, and a 

 report on the mechanical portion of the question by Mr. J. Scott Russell. 

 We present first an abstract of Dr. Gladstone's report. 



Chemical Report. Since the discovery of gun-cotton by Schonbein, 

 its application to war purposes has been frequently thought of; and 

 many experiments, with a view of using it, have been made, especially 

 by the French. Such serious difficulties have, however, presented 

 themselves, that the idea gradually came to be abandoned everywhere 

 but in Austria. Here experimentation was kept up, and it having 

 been reported on good authority that the experimenters had 

 succeeded in overcoming many of the difficulties encountered else- 

 where, the committee of the Association applied to the Austrian gov- 

 ernment for information, which was furnished them. The following is 

 a summary of the more important facts elicited. In the first place, the 

 gun-cotton prepared by Baron Von Lenk, the inventor of the Austrian 

 system, differs from the gun-cotton generally made in its complete con- 

 version into a uniform chemical compound. It is well known to chem- 

 ists that if cotton is treated with mixtures of strong nitric and sulphuric 

 acids, compounds may be obtained varying considerably in composition, 

 though they all contain elements of the nitric acid, and are all explo- 

 sive. The most complete combination (or product of substitution) is 

 that described as Co ? H 21 (9 NO 4 ) Ogo, which is identical with that 

 termed by the Austrian chemists trinitrocellulose, C 12 H T (3 NO 4 ) O 10 . 

 This is of no use whatever for the making of collodion ; but it is Von 

 Lenk's gun-cotton, and he secures its production by several precau- 

 tions, of which the most important are the cleansing and perfect dessic- 

 cation of the cotton as a preliminary to its immersion in the acids, 

 the employment 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 consequentim perfect conversion into gun-cotton, 

 the continuance of this steeping for forty-eight hours. Equally neces- 

 sary 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 evi- 

 dence before the committee it appears that this nitro compound, when 

 thoroughly free from acid, is not liable to some of the objections which 

 have been urged against that compound usually experimented upon as 



