The adoption of broadside batteries followed, therefore, necessarily upon increase of size and consequent length, but not upon that only. It is instructive to observe that the sailing fighting ship was derived, in part, at least, from the galley, and its resemblance in form to the latter is traceable for at least a century after the general disuse of the oar. As the galley, however, was small, it could concentrate its fire advantageously in one or two pieces, for which small number the cross-section offered a sufficient line of emplacement: and as, when it could move at all, it could move in any direction, there was a further advantage in being able to fire in the direction of its motion. Hence, bow fire prevailed in galleys to the end, although the great galleasses of Lepanto and the Armada had accepted broadside batteries in great part, and whenever the galley type has recurred, as on Lake Champlain during our Revolutionary War, bow fire has predominated. The sailing ship, on the contrary, was limited as to the direction in which she could move. Taking her as the centre of a circle, she could not steer directly for much more than half the points on the circumference. Bow fire consequently was much less beneficial to her, and, further, it was found that, for reasons not necessary to particularize, her sailing, steering, and manœuvring were greatly benefited by the leverage of sails carried on the bowsprit and its booms, projecting forward of the bow, where they interfered decisively with right-ahead fire. For all these reasons, bow fire disappeared and broadside fire prevailed; but the fundamental one to be remembered is the greater development of fire conferred by greater length. All ships—except the very small ones known as schooners, cutters, and gunboats—were broadside vessels, moved by canvas which was carried commonly on two or three masts; but into the particulars of the sails it is presumed readers will not care to enter. Being thus homogeneous in general characteristics, the ships of this era were divided commonly into three principal classes, each of which had subdivisions; but it was recognized then, as it is now in theory though too little in practice, that such multiplication of species is harmful, and our forerunners, by a process of gradual elimination, had settled down upon certain clearly defined medium types.