SAUVAGESIA, in botany, so named in honour of Francois Boissier de Sauvages, professor at Montpellier, a genus of the Pentandria Monogynia class and order. Natural order of Gruinales. Essential character: calyx five-leaved : corolla five petalled, fringed ; nectary five-leaved, al ternate with the petals ; capsule one-cell ed. There is but one species, viz. S. erects, a native of St. Domingo, Martinico, Jamaica, Surinam, and Guiana.
SAW, an instrument which serves to cut into pieces several solid matters, as wood, stone, ivory, &c. The best saws are of tempered steel, ground bright and smooth : those of iron are only hammer hardened : hence, the first, besides their being stiffer, are likewise found smoother than the last. They are known to be well hammered, by the stiff bending of the blade, and to be well and evenly ground, by theirbending equally in a bow. The edge in which are the teeth is always thicker than the back, because the back is to follow the edge. The teeth are cut and sharpened with a triangular file, the blade of the saw being first fixed in a whetting block. After they have been filed, the teeth are set, that is, turned out of the right line, that they may make the fissure the wider, that the back may fol low the better. The teeth are always set ranker for coarse cheap stuff than for hard and fine, because the ranker the teeth are set, the more stuff is lost in the kerf. The saws by which marble and other stones are cut have no teeth : these are generally very large, and are stretch ed out and held even by a frame. The workmen, who make the greatest use of the saw, are the sawyers, carpenters, joiners, cabinet-makers, cbonists, stone cutters, carvers, sculptors, &c. The la pidaries too have their saw, as well as the workers in mosaic ; but these bear little resemblance to the common saw. But, of
all mechanics, none have so many saws as the joiners ; the chief are as follows : the pit-saw, which is a large two-handed saw, used to saw timber in pits: this is chiefly used by the sawyers. The whip saw, which is also two-handed, used in sawing such large pieces of stuff as the hand-saw will not easily reach. The hand-saw, which is made for a single man's use, of which there are various kinds; as the bow or frame saw, which is furnished with cheeks : by the twisted cords which pass from the upper parts of these cheeks, and the tongue in the mid dle of them, the upper ends are drawn closer together, and the lower set further apart. The tenon-saw, which, being very thin, has a back to keep it from bending. The compass-saw, which is very small, and its teeth usually not set : its use is to cut a round, or any other compass•kerf hence the edge is made broad, and the back thin, that it may have a compass to turn in.
The surgeons also use a saw to cat off bones ; this should be very small and light, in order to be managed with the greater ease and freedom, the blade ex ceedingly fine, and the teeth exquisitely sharpened, to make its way more gently, and yet with great expedition, in cutting off legs, arms, &c.
Saws are now generally used by butch. era in separating the bones of the meat ; the divisions by the saw are neater than those by the chopper, and there is a cer tain saving, as the chopper splinters bones, the parts of which cannot be in cluded in the weight.