president's address — SECTION B. 101 



blow than when in the liquid condition. Some idea of the 

 "power" of this explosive can be gathered from the fact that, 

 \inder the most favorable conditions, 1 cub. foot of nitro-glycerine 

 on explosion would expand to 10,000 cub. feet of gas in the short 

 space of s-iTu^-o TT second. 



Picric acid, which is largely used as a dye, was first investigated 

 by Sprengel, in 1873, with regard to its properties as an explosive. 

 Exhaustive experiments were carried out by Colonel Majendie, 

 K.A., and Dr. Dupre, F.R.S., which went to show that picric acid 

 could be readily detonated by so small a quantity as five grains of 

 fulminate of mercury, and that such detonation would extend to 

 picric acid containing over 14 pei' Cetit. of water. In fact, when 

 detonated, this acid behaves very much in the same way as com- 

 pressed guncotton, as regards sensibility and the power of trans- 

 mitting the initial detonation of the dry material to the same 

 substance wetted. The products of the explosion of picric acid 

 are gaseous, and consist of aqueous vapour and actively poisonous 

 carbonic oxide. It is used in the manufacture of rhe French 

 smokeless powder known as " Melinite." 



The important discovery made a few years back by Mr. Alfred 

 Nobel, that a certain kind of collodion cotton was soluble in nitro- 

 glycerine, may be looked upon as the first step towards a new era 

 in smokeless explosives. This new explosive, known as " Blasting 

 Gelatine," consisting of 90 per cent, of nitro-glycerine and 10 per 

 cent, of collodion cotton, formed a very powerful compound, which, 

 "while suitable in an eminent degree for industrial purposes, was 

 found to be too violent for Service purposes. The pi-oblem had 

 yet to be solved, viz., how to tame this explosive, i.e., to impart 

 to it a sufficient energy for use in modern arms, combined with 

 certainty and regularity of propulsion. To the unscientific mind 

 this problem seemed easy of solution. The properties of guncotton 

 were well understood ; all that was required w^as a diluent or 

 retarding agent, to slow down the violence of explosiveness ; but 

 the first approach to success was again due to the imtiring perse- 

 verance of Mr. Alfred Nobel, who found that guncotton could be 

 incorporated with nitro-glycerine in equal jiroportions, and that 

 when combined in such proportions an explosive was formed, even 

 without the addition of any retarding agent, which w-as thoroughly 

 reliable for Service purposes. It is a curious fact that two of the 

 most violent explosives known, when combined, form a moderate 

 exjDlosive completely under control. The working out of this 

 observation has led to the production of one of the most valuable 

 of smokeless powders. This powder, known as " Ballistite " or 

 " C/89," consists of nitro-glycerine and guncotton, and is prepared 

 in the following manner : — 



The nitro-glycerine and guncotton are placed in a vessel and the 

 temperature raised by means of hot water, the contents being 

 agitated until the whole mass has gelatinised. It is then placed 



