88 On Recent Progress in the History of 
works of Messrs. Prentice, at Stowmarket, and at the 
Government Gunpowder Works at Waltham Abbey; its 
application to mining and artillery purposes, and to small 
arms, has been, and is still the subject of systematic ex- 
periment, conducted by the Government Committee on 
Gun-cotton; its employment as a blasting agent is 
steadily increasing in several important English mining 
districts; and considerable, though not uniform, success 
has already attended the employment of gun-cotton car- 
tridges for sporting purposes. | 
The system of manufacture of gun-cotton, as perfected 
by Baron Von Lenk, has undergone but trifling modifica- 
tions in its employment in this country. It has been 
made the subject of careful investigations by Mr. Abel, and 
the results furnished by many experimental manufacturing 
operations, and an examination of the products, have 
shown that the process of converting cotton into the most 
explosive form of pyroxylin or gun-cotton, and of purify- 
ing the material, have been so greatly perfected by Von 
Lenk as to render a strict adherence to his simple and 
precise instructions alone necessary to ensure the prepara- 
tion of very uniform products, which exhibit in their com- 
position a very much closer approximation to purity than 
those obtained in the earlier days of the history of gun- 
cotton. © 
Although the conclusions arrived at by the many 
chemists who investigated the composition of gun-cotton, 
soon after Schénbein’s discovery, varied very considerably, | 
the constitution has been very generally regarded as 
definitely established by the researches of Hadow, pub- 
lished in 1854. According to that chemist, the most 
explosive gun-cotton has the composition expressed by the 
formula C,H,N*O,, (which was first assigned to the sub- 
stance by W. Crum, in 1847), and may be regarded as 
cellulose, in which three atoms of hydrogen are replaced 
by three molecules of peroxide of nitrogen. The name 
trinitro-cellulose has therefore been assigned to gun- 
cotton, its constitution being expressed by the formula 
Co45 292 }O.- Hadow’s conclusions have been confirmed by 
other chemists, more especially by MRedtenbacher, 
Schrotter, and Schneider, who have analysed specimens of 
gun-cotton prepared under Von Lenk’s directions, Buta 
Report upon the Austrian Gun-cotton was published in | 
1864 by Pelouze and Maury, in which the formula — 
C,.H,.0,,,5 N,O is assigned to the product of Von — 
