uals 18,533
atmospheres, equals 19,151 kilogrammes. Applying this formula to gun-
cotton, and taking after Berthelot, Q = 1075, and after Vieille and
Sarrau, V_{o} = 671 litres, and _c_ as .2314, and the density of the
nitro-cellulose as 1.5, we have (V = O)

P = 671(1 + 1075/(273 x .2314))/.666 = 18,135 atmospheres.

To convert this into pressure of kilogrammes per square centimetre, it is
necessary to multiply it by the weight of a column of mercury 0.760 m.
high, and 1 square centimetre in section, which is equal to increasing it
by 1/30. It thus becomes

P^{k} = (1 + 1/30).

P^{k} = 18,135 x 1.033 = 18,733 kilogrammes.

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 |