1890.] on Smokeless Explosives. 17 



of which gun-cotton or some form of nitro-cellulose is the basis, and 

 of which those of Johnson and Borland, and of the Smokeless Powder 

 Company, are the most prominent in this country. 



In past years, both camphor and liquid solvents, such as acetic 

 ether and acetone, for gun-cotton, and mixtures of ether and alcohol 

 for nitro-cotton, have been ap])lied to the hardening of the surfaces 

 of compressed masses or granules of those materials, by von Forster 

 and others, with a view to render them non-porous, and in the E.G. 

 powder manufacture the latter solvent was thus applied to harden the 

 powder-granules. In the Johnson-Borland powder, camphor is applied 

 to the same purpose ; in smokeless powders of French and German 

 manufacture acetic ether and acetone have been used, and the solvent 

 has been applied, not merely to harden the granules or tablets of the ex- 

 plosive, but to convert the latter into a homogeneous horn-like material. 



Much mystery has surrounded the nature and origin of the first 

 smokeless powder adopted, apparently with undue haste, by the French 

 Government, for use with the Lebel magazine rifle. A few particles 

 of the Vieille powder, or Poudre B, were seen by the lecturer about 

 two years ago, and very small specimens appear to have fallen into 

 the hands of the German Government about that time. They were in 

 the form of small yellowish-brown tablets of about 0*07 inch to 

 • 1 inch square, of the thickness of stout notepaper, and had evi- 

 dently been produced by cutting up thin sheets of the material. They 

 appeared to contain, as an important ingredient, picric acid (the basis 

 of " melinite ") a substance extensively used as a dye, and obtained 

 by the action of nitric acid, at a low temperature, upon carbolic acid 

 and cresylic acid, constituents of coal tar. Originally produced by 

 the action of nitric acid upon indigo, and afterwards by similar treat- 

 ment of Botany Bay gum, it was first known as carbazotic acid, and 

 is one of the earliest of known explosives of organic origin. When 

 sufficiently heated, or when set light to, it burns with a yellow smoky 

 flame, and even very large quantities of it have been known to burn 

 away somewhat fiercely, but without exploding. Under certain con- 

 ditions, however, and especially if subjected to the action of a power- 

 ful detonator, it explodes with very great violence and highly 

 destructive effects, as pointed out by Sprengel in 1873, and recent 

 experiments at Woolwich have shown that it does this even, as in 

 the case of gun-cotton, when it contains as much as 15 per cent, of 

 water. It is no longer a secret that picric acid at any rate forms 

 the basis of the much-vaunted and mysterious explosive for shells 

 for which the French Government were said to have paid a very 

 large sum of money, and the destructive effects of which have been 

 described as nothing less then marvellous. M. Turpin patented, 

 in 1875, the use of picric acid alone as an explosive for shells and 

 for other engines of destruction, and whether or not his claims to be 

 the inventor of melinite are valid, there appears no doubt that his 

 patent in France was the starting-point of the development and adop- 

 tion of that explosive. 



Vol. XIII. (No. 84.) c 



