THE HISTOET OF EXPLOSIVE AGENTS. 
365 
2. When the solid substance with which gun-cotton is diluted consists of an oxidizing 
agent, the predisposition to chemical reaction between the two substances so far in- 
creases the susceptibility to detonation that, operating in conjunction with the effect of 
the soluble salt in imparting rigidity to the mixture, it renders the latter quite as sen- 
sitive to the detonating action of the minimum fulminate-charge as undiluted gun-cotton 
is when in a highly compressed condition. Some indication that the most powerful 
oxidizing agent furnishes, under these conditions, the material most susceptible of ex- 
plosion was afforded by the circumstance that the fuses containing only one grain of 
fulminate invariably inflamed fragments of the “ chlorate ” cylinders by their explosion, 
while the “ nitrate” cylinders were always scattered without ignition*. 
* Soon after the discovery of gun-cotton, attempts were made to increase the explosive force of that substance 
hy impregnating it with solid oxidizing agents, such as potassium nitrate ; hut the quantity of the salt which 
could he introduced into preparations of gun-cotton by the only practical mode of treatment (namely, hy im- 
pregnating these with a saturated solution and evaporating the water) was too small to render such treatment 
of any decisive practical value. The system of reducing gun-cotton to a fine state of division has afforded the 
means of readily incorporating this substance with the somewhat large proportion of saltpetre or analogous 
source of oxygen required for fully oxidizing the whole of the carbon in trinitrocellulose, and I have been 
successful in obtaining results of considerable practical importance in this direction. The general mode of 
producing “ nitrate ” or “ chlorate ” preparations of gun-cotton is as follows : — The requisite proportion of 
oxidizing agent, reduced to a very fine powder, is intimately mixed with the finely divided gun-cotton, with the 
aid of a saturated solution of the particular salt employed, and the mixture is granulated or compressed into 
any desired form by the usual pressure. Care is taken to make due allowance for the fluctuations in the 
amount of salt held dissolved by the water, consequent upon any change of temperature in the latter during 
the manufacturing operation, as well as for the extra amount of salt which will he deposited in the product hy 
the evaporation of the solution left in it after the pressing or granulating. The products obtained in this way, 
especially when compressed, form very hard masses, which are much less liable to break up or dust when 
roughly handled than ordinary compressed gun-cotton. The gradual evaporation of the water from them during 
the drying process causes part of the salt to crystallize throughout the mass, and thus the particles composing 
it become so firmly cemented together, that the application of considerably less pressure than is required to 
produce very compact cakes of gun-cotton suffices to furnish masses decidedly superior in hardness and com- 
pactness. The cakes or granules, when dry, are found to have become coated with a hard film of the salt, 
which acts as an additional protective against mechanical injury, and also renders them less readily inflam- 
mable than simple compressed gun-cotton. It has been, moreover, conclusively demonstrated, hy several experi- 
ments continued for considerable periods, that these preparations sustain continuous exposure to elevated 
temperatures without appreciable development of chemical change for much longer periods than the undiluted 
gun-cotton ; the distribution of saline matter throughout the mass operates protectively by impeding the trans- 
mission and consequent further development of any minute change established hy protracted exposure to heat 
in some particle of the mass of gun-cotton, which, however carefully prepared, cannot he absolutely uniform 
throughout in point of purity. 
Although the attainment of the maximum work from a given weight of gun-cotton demands the supply of 
oxygen sufficient for the complete oxidation of the carbon, and although, therefore, the products obtained hy 
incorporating gun-cotton with the full theoretical requirement of a chlorate or nitrate will develop considerably 
more explosive force than an equal weight of the simple gun-cotton, the most advantageous results are obtained? 
in actual practice, hy employing somewhat less than the full theoretical proportions of the oxidizing agent. 
Comparing the explosive action of equal weights of compressed gun-cotton and of the “ nitrate ” mixture pre- 
pared with the full proportion of the oxidizing agent (in which, therefore, about 38 per cent, of gun-cotton is 
