Originally the piece rested, as it were, fixedly on a massive support; but soon the means of sighting had to be considered; thus we see depicted in early manuscripts pieces that could be moved up and down by means of trunnions; or which were elevated or depressed for firing by a sort of tail or long projection behind the tube; at other times the muzzle of the cannon is sustained by a fork more or less buried in the ground. This bombard, attached to a platform on wheels, received the denomination of _cerbotana ambulatoria_; this last word conveying the idea of the movability of the engine. We have seen that projectiles were of stone, but there is no doubt that from the fourteenth century they were also made of metal; that was nothing new, for ancient engines of war, including the sling, threw leaden balls and masses of red-hot iron. No doubt it was with the object of giving the largest size possible to projectiles of artillery by means of powder that stone was used; which, in the state of the art at that time, was much better adapted than metal for large balls. Christine of Pisa, who wrote in the time of Charles VI. the “Livre des Faits d’Armes et de Chevalrie,” has left us a collection of very interesting details of the condition of artillery used with powder, which, as early as the fifteenth century, had become much more extended than would be easily believed; moreover, in the descriptions this author gives of armaments, or of narratives of battles, we almost always still see catapults, the large cross-bows, &c., appearing by the side of cannon; a certain proof that the use of powder found its equivalent in more than one instance in the ancient means of the propulsion of projectiles. [Illustration: Fig. 65.--Earliest Models of Cannon. In the Tower of London.] Valturio, an Italian writer, whose treatise on military art was first printed in 1472, has described and drawn all the engines of war then in use. Cannons are not forgotten. We observe that the greater number of these pieces have no longer any box forming a movable chamber; this implies an important advance in the art of making them; but, on the other hand, these cannons, bound with cords to a block of wood, or resting on platforms, must have been very difficult to move. At this period pieces of the largest calibre, which projected enormous balls of stone, were more commonly called _bombards_; mortars, the very short cannons throwing heated projectiles; cannons, pieces of medium calibre carrying iron projectiles (Fig. 65); culverins, the long pieces loaded with leaden balls, which, as well as the powder, were rammed in with an iron rod; hand-cannons, or _bâtons à feu_ (Fig. 66), were in a manner portable, for if they were handled by one man, it was never without his having recourse to another for firing them.