166 Mr. F. A. Abel on the [Feb. 5, 



17 per cent, of water, its detonation by fulminate direct was not certain 

 with the employment of less than about 13 grammes (200 grains), 

 whereas the result was absolutely certain with employment of about 10 

 grammes of air-dry gun-cotton. 



The transmission of detonation from dry to wet gun-cotton, through 

 the agency of a tube, appears to take place with the same facility as 

 though the mass to be detonated were dry ; and the same is the case with 

 regard to the propagation of detonation from one mass of moist gun- 

 cotton to others freely exposed to air, but touching each other, provided 

 the one first detonated contained not less water than the others to which 

 detonation is to be transmitted ; but this is not the case, if even small 

 spaces intervene between the separate masses, and in this respect the 

 moist gun-cotton behaves very differently from the air-dry material. 



The "nitrated" and "chlorated" preparations of gun-cotton are as 

 readily detonated, in the moist state, as ordinary compressed gun-cotton. 

 With respect to the mechanical effects obtained by the detonation of 

 these materials in the moist or wet state, numerous small and large com- 

 parative experiments have demonstrated that there is no falling off in the 

 work done by them when used wet. 



Decided evidence has, moreover, been obtained of greater sharpness of 

 action, when gun-cotton and its preparations are detonated in the wet 

 state ; and this accords with the observations made in the earlier of these 

 researches, that the less susceptible a mass of given explosive material is 

 of compression, when submitted to the action of a sufficient initiative 

 detonation, the more readily will detonation be transmitted, and the more 

 suddenly will the transformation from solid to gas and vapour take place. 

 When air is replaced by water in the compressed masses, the transmission 

 of detonation is obviously favoured by the increased resistance of the 

 particles to motion, at the instant of their exposure to the detonative 

 force. 



The freezing of wet compressed gun-cotton renders it as readily sus- 

 ceptible of detonation as the mixtures of gun-cotton with soluble (crys- 

 tallized) salts, to which the w^et material obviously becomes quite similar 

 in structure by the solidification of the water. 



Mercuric fulminate and mixtures of it with potassium chlorate, when 

 mixed with water to such an extent as to convert them into pasty masses 

 and freely exposed, are readily detonated by small quantities (0'2 grm. or 

 3 grains) of the confined fulminate, even when not in contact. Finely 

 divided gun-cotton, made up into a pulp with water, was found not to 

 be susceptible of detonation, even under very much more favourable con- 

 ditions than the above, the mixture being placed in thin metal cylinders, 

 open at one end, and a large disk of dry gun-cotton detonated in the 

 centre. But if wet compressed gun-cotton is packed into receptacles of 

 wrought iron, so that the initiative charge of dry gun-cotton is closely 

 surrounded by it, and the small spaces intervening between the several 



