But it is not only the gun itself that has been improved; the powder has also been improved, and to a degree almost equal, if not quite. When we realize that modern gunnery is so exact that if a gun is fired in any direction and at any angle of elevation, the projectiles will fall so close to a designated spot that all considerable variations in the points of fall from that spot are usually attributed to other causes than imperfection in the powder; and if we realize also that a variation of one per cent. in the initial velocity imparted to a projectile by its powder would result in a variation (practically speaking) of one per cent. in the range attained, we then may realize how perfectly understood the laws of the combustion of powder and the development of powder gas have become, and how perfect are the methods of manufacturing, storing and using it. Books upon books have been written on the subject of making and using gunpowder; and as high a grade of experimental ability has been employed as on the development of any other art. It is not quite clear whether stationary cannon or small guns carried by soldiers were the first to be used; but the probability seems to be that cannon were the first. It soon became desirable to devise and to make appliances for holding the cannon in position, elevating them to predetermined angles, and transporting them from place to place. To accomplish these things, gun-carriages were invented. These appliances have kept pace with guns and gunpowder in the march of improvement; countless minor inventions have been made; countless experiments have been conducted; countless books and articles have been written; countless millions of money have been expended. That the field has been large can readily be realized, when we remind ourselves of the numberless situations that gun-carriages have had to be adapted to, on the level plains of Central Europe, in the mountains, on the sands of the desert,--in cold and heat and wet; and on the ocean also, in small vessels and great battleships, to handle cannon great and small, on the uneasy surface of the sea. But it will not be enough for us to realize that it has been necessary to construct gun-carriages so ingeniously that guns can be handled on them under all these circumstances; for we will fall short of a realization of what must be attained, unless we realize that the guns must be handled with safety, and (which is more difficult of attainment) with precision and yet with quickness. Now to bring the gun and its accessories to the high standard they have now reached, the resources of virtually all the physical sciences have been required and utilized; so that, while modern civilization was made possible by the gun, and could not have been made possible without it, the modern gun has been made possible by civilization, and could not have been made possible without it.