Page:Popular Science Monthly Volume 51.djvu/156

146 With the construction and use of the materials employed in modern warfare none but the professional military engineer can be reasonably expected to attain much familiarity. But all have an interest in national preparation for contingencies, and even to the nonprofessional it may be an engaging study to trace in outline the evolution of the cannon as now made at great armories like that at Watervliet, near Troy, New York.

It would be only repeating an oft-told tale to show that our remote human ancestors were all savages, and that the normal condition of society among them was that of warfare. What were the earliest weapons employed we can only conjecture. If we disregard the long and for the most part unknown period that preceded the beginning of definite human records, we find that when these records began man was already acquainted with the ruder processes of metallurgy. But there are no indications that during the age of universal savagery metal was used to any great extent for projectile purposes. Arrows and javelins were early and abundantly employed, and the use of the sling was undoubtedly common among the Israelites long before the dramatic duel between David and Goliath. The Romans in conducting their sieges employed the catapult and ballista for the projection of large arrows and stones; but from the vague description of these instruments we can glean little more than that they were probably immense crossbows. They were unwieldy, but powerful enough to project stones, each as heavy as an ordinary man, over a distance of a hundred yards. During the first dozen centuries of the Christian era there was but little improvement over Roman methods of warfare.

That the elastic force of hot gas suddenly evolved should be substituted for that of a stout cord under great tension could not have been possible without the previous discovery of the means by which such gas could be appropriately generated. There is no probability that we will ever learn definitely the true history of the invention of gunpowder. Quite probably it was independently invented by different persons at different times. There can be little doubt that the knowledge of its composition existed at a very early date among some of the inhabitants of India, where the rich soil under a tropical sun has during many centuries been leached for the purpose of procuring niter. Assuming the presence of this salt in abundance, it would hardly be possible for one who handles it to remain long ignorant of its capacity to explode when sufficiently heated in contact with charcoal, sulphur, or any other kind of fuel. It is not surprising that some of the earlier alchemists should be credited with the preparation of gunpowder. It has been common to attribute its invention to Roger Bacon, whose life lasted through the greater part of the