The complicated methods by which a fortress was captured or a town carried during the Middle Ages are not generally known, and the means adopted at the present time are as a general rule credited with being the outcome of the skill and science of the past few centuries. This, however, will not bear the test of investigation, for we find that almost every device has had its prototype in past ages, and nearly every idea has been forestalled. It comes almost with a shock to some, and produces feelings of incredulity, to be told that huge missiles vieing in destructive effect with the modern shell, and as a rule many times larger, were sent with unerring aim into the heart of a besieged town, levelling houses to the ground and dealing destruction far and wide. The idea of a siege in mediæval times is generally that of a tree to batter down a door, archers to shoot down the defenders on the walls, desperate charges of cavalry against sallies of the garrison, and forlorn hopes of men carrying scaling-ladders with which to surmount the walls. These are, however, only a few concomitants of the complicated methods by which a siege was accomplished. The Greeks and Romans constructed their engines upon the principle of the bow, whereas the mediæval engineers adopted that of the sling. The latter was by far the more clumsy of the two, but probably just as effective. Had the methods by which the Greeks were enabled to construct their splendid engines been handed down, the possibility is that mediæval machines would have been far less cumbersome and much smaller. Probably the greatest living authority upon projectile-throwing machines is Sir Ralph Payne-Gallwey, Bart., who has constructed models of ancient and mediæval machines with most successful results. He says, “My engines are by no means perfect in their mechanism, and are always liable to give way under the strain of working. One reason of this is that all modern engines of the kind require to be worked to their utmost capacity, _i.e._ to the verge of their breaking-point, to obtain from them results that at all equal those of their prototypes. The ancient engines did their work easily and well within their strength. Although my largest catapult will throw a stone to a great distance it cannot throw one of nearly the weight it should be able to do, considering the size of its frame, skein of cord, and mechanism. In this respect it is decidedly inferior to the ancient engine.”[1] The author of the above has, however, been able to construct a catapult which throws a stone of 8 lbs. to a distance of between four hundred and fifty and five hundred yards.