Jan. 1, 1865.] THE TECHNOLOGIST. 



PROPERTIES AND USES OF GUN-COTTON. 257 



fices to wash one thousand bushels in a day, which in a deposit like that 

 of Riviere du Loup would contain about seventy-three pennyweights 

 of gold. It is probable, however, that a certain portion of the finer gold 

 dust, which is collected in the ordinary process, would be lost in work- 

 ing on the larger scale. It has already been shown that the gold is not 

 confined to the gravel of the river channels, and the alluvial flats. The 

 beds of interstratified clay, sand, and gravel, which occur on the banks 

 of the Metgermet, were found to contain gold throughout their whole 

 thickness of fifty feet, and even though its proportion were to be many 

 times less than in the gravel of the Riviere du Loup, these thick deposits, 

 which extend over great areas, might be profitably worked by the 

 hydraulic method. The fall in most of the tributaries of the Chaudiere 

 and of the St. Francis, throughout the auriferous region, is such that it 

 will not be difficult to secure a supply of water with a sufficienthead, 

 without a very great expenditure in the construction of canals ; and it 

 may reasonably be expected that before long the deposits of gold-bearing 

 earth, which are so widely spread over South-Eastern Canada, will be 

 made economically available. 



PROPERTIES AND USES OF GUN-COTTON. 



BY W. PROCTER, M.D. 



Gun-cotton, since the time of its discovery, has been regarded as a sub- 

 stance of great interest, both on account of the singular properties it 

 presents to the chemist, and for its numerous useful applications under 

 the form of collodion. But lately it has assumed new and greater 

 importance in another direction, consisting in the probability that its 

 substitution for gunpowder, which was attempted unsuccessfully, shortly 

 after its discovery, and failed, will now be carried into operation, arising 

 from inrproved processes of manufacture, and the results of experiments 

 which have shown that the slow or rapid combustion of gun-cotton 

 depends on its mechanical arrangement and condition. 



Gun-cotton is a modification of lignin, the basis of vegetable fibre, 

 by which a new element, nitrogen, is introduced into its composition. 

 In 1815 Braconnot gave an account of an explosive compound obtained 

 by the action of nitric acid on starch, and to which he gave the name of 

 " xyloidin." In 1838 Pelouze observed that nitric acid produced a similar 

 change in paper, and in 1846 Schonbein announced that he had discovered 

 a new explosive compound which he believed would prove a substitute 

 for gunpowder, and was the result of the action of a mixture of 

 nitric and sulphuric acids upon cotton. This announcement and a 

 demonstration of the properties of gun-cotton attracted very general 



