Page:Popular Science Monthly Volume 56.djvu/458

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T is apparent that the range of even the most highly perfected torpedo is comparatively short, while their accuracy of travel is low. Besides, their propelling, controlling, and discharging mechanisms are complicated, delicate, and easily deranged, they are very expensive, and not only the explosive chamber but the entire system is destroyed in use. The superiority of gunpowder guns as a means of throwing projectiles to great distances with accuracy is well known, and their capacity for safely and efficiently projecting shells filled with gunpowder has long been demonstrated. It was obvious that as the superior destructive power of dynamite, gun cotton, and other high explosives became known and their commercial manufacture was assured, attempts would be made to employ them as bursting charges for shells. Experiments to demonstrate how this might be done and what effects could be expected were begun more than forty years ago, and have been continued in many different places from time to time ever since; but while it has proved that small charges might be fired with low velocities and pressures in ordinary shell, and large charges in specially constructed shell or in specially prepared forms of charge, with comparative safety so far as the premature explosion of the explosive charge itself is concerned, yet these bodies are so sensitive to the shock resulting from the discharge of the propellant, the heat generated by its combustion, and that arising from friction in the "set-back" of the shell charge and the rotation imparted by the rifling, that they can not be safely fired from modern high-power guns under service conditions, particularly as these explosives all require that the shell shall be fitted with a detonator in order that the charge may be fully exploded. The most promising results with explosives of this class have been obtained with compressed wet gun cotton, which has been packed directly in the shell in rigid blocks completely filling the shell cavity, or cut in cubes and