“The nitre contains five primes of oxygen, of which three combining with the three of charcoal, will furnish three of carbonic oxide gas, while the remaining two will convert the one prime of sulphur into sulphurous acid gas. The single prime of nitrogen is therefore, in this view, disengaged alone. “The gaseous volume, in this supposition, evolved from 136 grains of gunpowder, equivalent in bulk to 75-1/2 grains of water, or to three-tenths of a cubic inch, will be, at the atmospheric temperature, as follows:-- Grains. Cubic Inches. Carbonic oxide 42 141·6 Sulphurous acid 32 47·2 Nitrogen 14 47·4 ----- 236·2 being an expansion of one volume into 787·3. But as the temperature of the gases, at the instant of their combustive formation, must be incandescent, this volume may be safely estimated at three times the above amount, or considerably upwards of 2,000 times the bulk of the explosive solid. “It is obvious that the more sulphur, the more sulphurous acid will be generated, and the less forcibly explosive will be the gunpowder. This was confirmed by the experiments at Essonne, where the gunpowder that contained twelve of sulphur, twelve of charcoal, in 100 parts, did not throw the proof shell so far as that which contained only nine of sulphur and fifteen of charcoal. The conservative property is, however, of so much importance for humid climates and our remote colonies, that it justifies a slight sacrifice of strength. “When in a state of explosion, the volume,” Dr. Hutton calculates, “is at least increased eight times, and hence its immense power. The pressure exerted, if in a state of confinement, will depend on the dimensions of the vessel containing it; so that it would be no difficult undertaking to obtain any pressure above that of the atmosphere, up, we may fearlessly say, to the enormous amount of 4,000 lbs. per square inch.” The same quantity of gunpowder subjected to a variety of experimental tests, differs materially in its results; at the same time it is only by such a method that we can arrive at the relative strength or power which it possesses. Dr. Hutton, whose authority in all mathematical calculations is very high, and whose opinions and judgment in matters of this nature ought not to be unthinkingly controverted, states 2,000 feet per second (with cannon) as the highest velocity which any projectile had attained, at the time of his writing, which had gunpowder for its propellant power. A much greater velocity is now given in all guns fired at high elevations. “Monks’” gun attained a velocity of 2,400 feet in the first second of its flight, and this is now exceeded by rifled cannon.