The true science of gunnery consists in knowing that a certain force is requisite to effect a certain purpose, or, in other words, to kill at a certain distance; and also how to arrange that force so as to effect the purpose without having any extra _force_, or any waste of powder, nor yet too little, but with a corresponding result: a sufficiency; neither more nor less. This we have shown is attainable by the mechanical arrangement of granulation; for it is useless to use less, or to use an iota more of fine grain powder, if the size larger will effect the purpose without that iota. Propellant velocity is the grand desideratum in all gunnery; the obtainment of this, to the greatest extent, is the power of killing at the greatest distance: all ranges are dependent on velocity; no extreme _range_ can be obtained without a corresponding speed. The very finest powder, it will be perceived, is fitted--perfectly fitted, preferable, indeed--to coarser grain for guns of a short length of tube, where a perfect combustion of the whole charge can be obtained without any waste or want; but as such is quite unsuited for longer barrels: I cannot too often repeat it. The column of air is the ruling power. Look what its effects are by Hutton’s calculations, with the very low velocities he obtained! So great as to bring all projectiles he used to a medium velocity, before they were projected beyond a certain distance. Then what must its resistance be where the velocities are trebled? I say trebled, for my powder and the percussion combined have more than trebled the velocities. You must then clearly have a powder of such grain as suits the capacity of your gun. All barrels have a size of grain that will suit them best, and manufacturers of gunpowder will consult their own profit and the convenience of sportsmen, if they assimilate the grain of powder to various sizes; as in shot, to No. 1, No. 2, 3, 4, 5, and so on: eventually this system must be adopted. This will explain quite clearly how the fact (singular to many) occurs, of short guns excelling their longer competitors, and how frequently a particular maker obtains an immensity of credit for an excellent gun only twenty-two inches: “Beat my Lord So-and-so’s of thirty inches!” and how, “When I cut four inches off my double, she shot better than ever she did.” All these occurrences are perfectly dependent on a knowledge of the generating of the explosive force, and may be reversed at any time by a person possessed of sufficient knowledge of these facts: put in coarse grain into the short gun, and fine into the long, and the facts will be changed considerably, as will be easily seen. A degree of mystery has hitherto existed as to the cause of this discrepancy; but I trust this explanation will clear it up.