The following tables, taken from Messrs William Macnab’s and E. Ristori’s paper (Proc.  Roy.  Soc., 56, 8-19), “Researches on Modern Explosives,” are very interesting.  They record the results of a large number of experiments made to determine the amount of heat evolved, and the quantity and composition of the gases produced when certain explosives and various smokeless powders were fired in a closed vessel from which the air had been previously exhausted.  The explosions were carried out in a “calorimetric bomb” of Berthelot’s pattern.[A]

[Footnote A:  For description of “bomb,” see “Explosives and their Power,” Berthelot, trans. by Hake and Macnab, p. 150. (Murray.)]

Table Showing Quantity of Heat and Volume and Analysis of Gas Developed per Gramme with Different Sporting and Military Smokeless Powders Now In Use

_______________________________________________________

_______________
|          |           |         |              |
Name of Explosive.   | Calories | Permanent | Aqueous | Total Volume |
| per grm. |  Gases.   | Vapour. | of Gas at 0 deg. |
|          |           |         |  and 760 mm. |
______________________|__________|___________|_________|____

__________|
|          |  cc/grm   | cc/grm  |    cc/grm    |
E.C. powder, English |    800   |    420    |   154   |     574      |
S.S. powder          |    799   |    584    |   150   |     734      |
Troisdorf, German    |    943   |    700    |   195   |     895      |
Rifleite, English    |    864   |    766    |   159   |     925      |
B.N., French         |    833   |    738    |   168   |     906      |
Cordite, English     |   1253   |    647    |   235   |     882      |
Ballistite, German   |   1291   |    591    |   231   |     822      |
Ballistite, Italian  |   1317   |    58l    |   245   |     826      |
and Spanish        |          |           |         |              |
______________________|__________|___________|_________|____

__________|

The figures in column headed “Co-efficient of Potential Energy” serve as a measure of comparison of the power of the explosives, and are the products of the number of calories by the volume of gas, the last three figures being suppressed in order to simplify the results.

The amounts of water found were calculated for comparison as volumes of H_{2}O gas at 0 deg. and 760 mm.

E.C. powder consists principally of nitro-cellulose mixed with barium nitrate and a small proportion of camphor.

S.S. of nitro-lignine mixed with barium nitrate and nitro-benzene.

Troisdorf powder is gelatinised nitro-cellulose; rifleite gelatinised nitro-cellulose and nitro-benzene.

Cordite contains 58 per cent. nitro-glycerine, 37 per cent. gun-cotton, and 5 per cent. vaseline.

Ballistite (Italian) consists of equal parts nitro-cellulose and nitro-glycerine, and 1/2 per cent. of aniline.  The German contains a higher percentage of nitro-cellulose.