1S79.] on Hccvvi DcfoudfliKj A</('iifs. 77 



propagation of detonation from one mass of moist gun-cotton to 

 another, in open air, all the pieces being ranged in a row, in contact 

 with each other, provided that the piece first detonated does not 

 contain less water than the others to which detonation is transmitted. 

 Some curious results, obtained in exjieriments on the transmission of 

 detonation, with gun-cotton containing ditierent proj)ortions of water, 

 appeared to indicate that the character or quality of detonation 

 developed by gun-cotton is subject to modification by the projiortion 

 of water which the latter contains. 



Gun-cotton containing 12 to 14 per cent, of water is ignited with 

 much difficulty on applying a highly heated body. As it leaves 

 the hydraulic press upon being converted from the pulped state to 

 masses having about the density of water, it contains about 15 per 

 cent, of water ; in this condition it may be thrown on to a fire or 

 held in a flame without exhibiting any tendency to burn ; the masses 

 may be perforated by means of a red-hot iron or with a drilling tool, 

 and they may wdth perfect safety be cut into slices by means of saws 

 revolving with great raj^idity. If placed upon a fire and allowed to 

 remain there, a feeble and transparent flame flickers over the surface 

 of the wet gun-cotton from time to time as the exterior becomes 

 sufficiently dry to inflame ; and in this way a piece of comj^ressed 

 gun-cotton will burn away very gradually indeed. A pile of boxes 

 containing in all 6 cwt. of gun-cotton, impregnated with about 

 20 per cent, of water, when surrounded by burning wood and 

 shavings in a wooden building, was very gradually consumed, the 

 gun-cotton burning as already described when the surfiices of 

 the masses became j)artially dried. In two other experiments 

 quantities of wet gun-cotton of 20 cwt. each, packed in one instance 

 in a large, strong wooden case, and, in the other, in a number 

 of strong packing cases, were placed in small magazines, very sub- 

 stantially constructed of concrete and brickwork. Large fires were 

 kindled around the packages in each building, the doors being just 

 left ajar. The entire contents of both buildings had burned away, 

 without anything approaching explosive action, in less than two 

 hours. This comparatively great safety of wet gun-cotton, coupled 

 with the fact that its detonation in that condition may be readily 

 accomplished through the agency of a small quantity of dry gun- 

 cotton, which, through the medium of a fulminate fuze or detonator, 

 is made to act as the initiative detonating agent, gives to gun-cotton 

 important advantages over other violent explosive agents for purposes 

 which involve the employment of more or less considerable quan- 

 tities at one time, on account of the comparative safety attending its 

 storage and the necessary manipulation of it. Moreover, it has been 

 well established by experiments of many kinds carried out on a 

 considerable scale, as well as by accurate scientific observations, that 

 the detonation of wet gun-cotton is decidedly sharper or more violent 

 than that of the dry material ; a circumstance which afibrds an 

 interesting illustration of the influence exerted by the physical 



