10 Sir Frederick Abel [Jan. 31, 



At the time that our attention was first actively given to this 

 subject of the modification of the ballistic proj^erties of powder, it had 

 already been to some extent dealt with in the United States by 

 Kodman and Doremus, and the latter was the first to propose the 

 application, as charges for guns, of powder-masses produced by the 

 compression of coarsely grained powder into moulds of prismatic 

 form. In Russia the first step was taken to utilise the results arrived 

 at by Doremus, and to adojjt a prismatic powder for use in guns of 

 large calibre. 



Side by side with the development and perfection of the manu- 

 facture of prismatic powder in Russia, Germany, and in this country, 

 new experiments on the production of powder-masses suitable, by their 

 comparatively gradual action, for employment in the very large charges 

 required for the heavy artillery of the present day, by the powerful 

 compression of mixtures of more or less finely broken up powder-cake 

 into masses of greater size than those of the i)ebble, pellet, and 

 j^rism powders, were actively pursued in Italy, and also by our own 

 Government Committee on Explosives, and the outcome of very 

 exhaustive practical investigations were the very efficient Fossano 

 powder, or poudre progressif, of the Italians, and the boulder and 

 large cylindrical powders known as P^ and C^, produced at \A'altham 

 Abbey, which scarcely vied, however, wdth the Italian powder in the 

 uniformity of their ballistic properties. 



Researches carried out by Captain Noble and the lecturer some 

 years ago with a series of gunpowders differing considerably in com- 

 position from each other, indicated that advantages might be secured 

 in the production of powders for heavy guns by so modifying the 

 proportions of the constituents (e. g. by considerably increasing the 

 proportion of charcoal and reducing the proportion of sulphur) as to 

 give rise to the production of a much greater volume of gas, and at 

 the same time to diminish the heat developed by the explosion. 



These researches served, among other purposes, to throw con- 

 siderable light upon the cause of the wearing or erosive action of 

 powder-explosions upon the inner surface of the gun, which in time 

 produces so serious a deterioration of the arm that the velocity of 

 projection and accuracy of shooting suffer very greatly, an effect the 

 extent of which increases in an increasing ratio to the size of the 

 guns, in consequence, obviously, of the large increase in the weight 

 of the charges fired. 



Several causes undoubtedly combine to bring about the wearing 

 away of the gun's bore, which is especially great where the products 

 of explo.sion, wliile under the maximum pressure, can escape between 

 the projectile and the bore. The great velocity with which the 

 very highly heated gaseous and liquid (fused solid) products of ex- 

 plosion sweep over the heated surface of the metal gives rise to a 

 displacement of the particles composing it, which increases as the 

 surface becomes roughened by the first action upon the least compact 

 portions of the metal, and thus opposes greater resistance ; at the 



