Thus considered, artillery was not a very effective instrument. And, just as in earlier times it had been sought to supplement mere impact by other effects--by the throwing into besieged fortresses of quicklime, for instance, “dead horses and other carrion,”--so, after the arrival of gunpowder, endeavour was made to substitute incendiarism or explosion for the relatively ineffective method of impact. The use of grenades, hand-thrown, was discovered. And then followed, as a matter of course, their adaptation to the mortars already in use for the projection of stones and other solid material. These mortars, as in the case of the early cannon, were at first made of an inconveniently large size; and, also as in the case of cannon, they came later to be cast of more moderate proportions to facilitate their transport and thus render them more serviceable for operations in the field. Artillery was now devoting its attention to the personnel. The result of this evolution was the howitzer, a weapon whose value to land armies was greatly enhanced by the discovery, by Marshal Vauban at the end of the seventeenth century, of the efficacy of the _ricochet_. Under this system the fuzed bomb or grenade, instead of being projected from a mortar set at a high elevation, to describe a lofty and almost parabolic trajectory, was discharged from a howitzer at a sufficiently low elevation to cause it to strike the ground some distance short of its objective, whence it proceeded, leaping and finally rolling along the ground till it came to its target, where it exploded. [Illustration]