cular saws by
electricity, steam or gas.

Carpentry or carpenters' work has been divided into three principal
branches--descriptive, constructive and mechanical. The first shows the
lines or method for forming every species of work by the rules of
geometry; the second comprises the practice of reducing the timber into
particular forms, and joining the forms so produced in such a way as to
make a complete whole according to the intention or design; and the
third displays the relative strength of the timbers and the strains to
which they are subjected by their disposition. Here we have merely to
describe the practical details of the carpenter's work in the operations
of building. He is distinguished from the joiner by his operations being
directed to the mere carcass of a building, to things which have
reference to structure only. Almost everything the carpenter does to a
building is absolutely necessary to its stability and efficiency,
whereas the joiner does not begin his operations until the carcass is
complete, and every article of joiners' work might at any time be
removed from a building without undermining it or affecting its most
important qualities. Certainly in the practice of building a few things
do occur regarding which it is difficult to determine to whose immediate
province they belong, but the distinction is sufficiently broad for
general purposes.

The carpenter frames or combines separate pieces of timber by scarfing,
notching, cogging, tenoning, pinning and wedging, &c. The tools he uses
are the rule, axe, adze, saws, mallet, hammers, chisels, gouges, augers,
pincers, set squares, bevel, compasses, gauges, level, plumb rule, jack,
trying and smoothing planes, rebate and moulding planes, and gimlets and
wedges. The carpenter has little labour to put on to the stuff; his
chief work consists in fixing and cutting the ends of timbers, the
labour in preparing the timber being done by machinery.

[Illustration: FIG. 1.--Lapped Joint.]

[Illustration: FIG. 2.--Fished Joint.]

[Illustration: FIGS. 3, 4 and 5.--Scarf Joints.]

_Joints._--The joints in carpentry are various, and each is designed
according to the thrust or strain put upon it. Those principally used
are the following: lap, fished, scarf, notching, cogging, dovetailing,
housing, halving, mortice and tenon, stub tenon, dovetailed tenon, tusk
tenon, joggle, bridle, foxtail wedging, mitre, birdsmouth, built-up,
dowel. Illustrations are given of