Considering the difference between gunpowder in 1783 and gunpowder in 1858, I cannot say, with Hutton, that the force is doubled now to what it was when he wrote; but I believe that this would not be far from the truth; for it must be quite clear--if he is correct (which I believe he is) in saying the force of gunpowder consists in the quantity of explosive matter let loose and expanded by heat--that the greater the quantity of condensed matter we may have in any given weight, the greater the force, and the more rapid the explosion: purified saltpetre thus forming nearly pure gaseous matter; as the diamond is pure carbon. It seems singular, and is rather presumptuous to say, that Hutton was not much of a chemist; but had he been more so, he must have perceived that in the extraction of the foreign matter from the nitre, existed the means of obtaining an increased quantity of explosive power, and a proportionate increase of speed or velocity in that explosive material. To ascertain the velocity best suited to all projectiles, constitutes the germ of the science; and that we are approaching a new era in even that more intimate portion of the science, is daily apparent. Science shows clearly that if a given force, a quantity to be correctly ascertained, can produce a certain result, the use of more is waste, and unworthy of the seeker after perfection; and thus we have to determine upon, or define, what is the degree or size of gun for certain effects: a mere calculation nearly allied to that portion of engineering which would define what power of engine would work a thousand cotton spindles, or raise a million gallons of water; and all this will eventually be done. Science requires that there should be no excess, no waste, no unnecessary recoil, and all that combined with the utmost range of projectile; this will have to be defined accurately before we can clearly or truly say we are masters of the science of gunpowder. True it is that the granulation of gunpowder gives a clear road to its attainment; but it will be a wearisome journey to reach the summit: yet it must and will be effected, and the nation that first attempts and carries out the attainment, will evince a real love for and mastery of science. The following practical experiments illustrate the degree of velocity and the effects of projectiles so clearly, that they alone will convey some idea of the high velocity of the evolutions of the gases in gunpowder.