tool used by mechanics, which consists of an iron head fixed crosswise upon a handle. The hammers used by blacksmiths are of several kinds; as, the hand-hammer, which may be wielded with one hand at the anvil; the up-hand sledge, used with both hands, and seldom lifted above the head; the about-sledge, which is the largest of all, and held by both hands at the furthest end of the handle, and, being swung at arm's-length over the head, is made to fall upon the work with a heavy blow. There is also the riveting hammer, which is the smallest of all. Carpenters and other artisans have likewise hammers suited to their several purposes.

The name of steam-hammer has been given to various powerful machines worked by steam, for dealing heavy blows with rapidity and precision. The steam-hammer of Mr Nasmyth, the introducer of this machine, is particularly deserving of mention, as greatly economizing time and labour, and for its successful employment in ironmaking, the forging of anchors, pile-driving, &c. See Iron-Making.

Hammerfest, a town of Norway. See Lapland.