This advantage does not arise, in our opinion, so much from the superior quality of the gunpowder, as from the improvements which have taken place in the manner of applying it. For instance, where experiments are conducted, as was the case with Dr. Hutton, with moving _eprouvettes_, a certain loss is sustained, in the same degree as the instrument is made to recoil from its original position; therefore, by restraining the recoil, an increase of momentum is given to the projectile, to the same extent as had been exerted upon the _eprouvette_, or cannon, in driving it several feet backward; and instead of dividing the force thus acquired between the shot and the gun, by having the latter firmly fixed and the recoil destroyed, the whole power is exerted upon the former, and its velocity accelerated in the same proportion. Gunpowder, though astonishing in its effect, and tremendous in power, may nevertheless be controlled within a limited sphere, and bounds put upon its destructive energy. The following curious experiment, first tried at Woolwich on a small scale, has since been carried out to a great extent. Screw into each end of the breech part of a gun-barrel a well-fitted plug; drill a communication, and put in a nipple; having filled the barrel with powder, screw in the breech, and fire a cap on it, and the explosive fluid will escape by the small orifice like steam from a pipe. If the barrel be good, it may safely be held in the hand, merely using a towel to protect the hand from the heat the barrel absorbs. We have done it repeatedly with no inconvenience, and even carried this experiment much further; firing two ounces of the best powder in a barrel of good quality (though not in the hand) yet the barrel did not receive any violent motion by which it could be inferred that it might not be done with safety. We have before observed, that, with very short guns, fine gunpowder produces the greatest result, inasmuch as there is no greater column of air in the barrel than the explosive fluid is equal to _displace_; or, in other words, the charge leaving the muzzle of the gun at the very moment when the explosive force is strongest, all the power is thus obtained of which it is capable; but if used in a longer barrel, and the fluid has obtained its greatest power when the charge has twelve inches of the barrel still to travel, the column of compressed air yet remaining in the muzzle of the barrel, exerts a resisting influence, in proportion to its density, upon the charge, and creates a dangerous and unpleasant recoil.