The carpenter has always been a worker in wood and probably will always be so, unless we are so foolish as to neglect the newer art of Forestry to such an extent that in the course of time we have no wood wherein to work and with which to build and decorate our habitations. The building and the decoration of houses and other structures has always been the special contribution of the carpenter to the general welfare of the community, and this feature has distinguished him from other woodworkers such as carriage builders, shipbuilders, coopers, and makers of various implements. But whereas the carpenter formerly did all the work connected with the building or decoration of the structure, he now perforins only a small part of it. At one time he was called upon to prepare the rough lumber for framing, erect the building, make the doors and windows together with their frames, and then make and put in place all the outside and inside finish, even including the furniture. In these days, however, factories are doing a great deal of this work, such as the manufacture of doors and window sash, interior finish, furniture, etc., and the lumber which was formerly prepared by hand is now sawed, cut, planed, molded, and even sandpapered by machinery, leaving for the carpenter the preparation of the framing of such buildings as are not large enough to be built of brick, stone, or steel, and the putting in place at the building of the exterior and interior finish which has previously been made ready so far as possible at the factory. The old-time joiner has given way to the modern cabinet maker or the factory woodworker, and his plane, saw, and chisel have been replaced by electrically-driven machinery of the planing mill and the door factory. Nevertheless, the principles upon which the art of carpentry is based have not changed, and we still use the formulas, and profit by the wisdom which has come down to us from our fathers.

Copyright, 1912, by American School of Correspondence.

The carpenter has always found at hand his material provided by Nature, needing only to be cut down and shaped to suit his purposes. It is easily worked, beautiful in texture, and capable of being treated with paints, oils, and varnishes in such a way as to preserve it and at the same time give it a pleasing appearance. So suitable is wood for purposes of interior decoration that now when other materials such as sheet metal are substituted for it on account of their greater durability or their superiority as fire resistants, great pains are often taken to make these materials look like wood by the skillful use of paints and varnishes, and such good results have been obtained along this line, and the grain of the various kinds of wood has been so closely imitated, that one not accustomed to woodwork in a business way can hardly distinguish the real wood from the imitation.

A knowledge of the characteristics of this material which plays so important a part in our lives and which is so plentiful, especially in the more recently settled parts of the earth, is sure to prove of advantage to all, and such knowledge is an absolute necessity to the carpenter, architect, or other user of wood.

Unlike many of the other materials used in building, wood has life and has come into existence by a process known as growth, and these two facts have a very important bearing on the use of wood in construction, as they affect both its physical characteristics and its action after it has been put in place in a building. In order, therefore, to be able to make use of wood intelligently, it is necessary to know something about its mode of life, its method of growth, and the way in which it will act after it has been cut away from the tree, killed, so far as it is possible to kill it, by seasoning or drying, and then setting up in place. All woods are not the same in these respects; in fact, no two kinds of wood are exactly the same in structure, nor will they behave in the same way even under the same conditions, and this makes it necessary to select them very carefully for various purposes and for use in various places.

While it is true that no two kinds of wood are exactly the same in structure, they still have some things in common. For example, all wood is a vegetable product, and all wood is built up in the same general way out of a very great number of individual parts called cells, or fibers, which are like so many tiny pockets filled with a fluid substance. The size, shape, and arrangement of these little cells is different in different kinds of wood, and this accounts for the differences in appearance, texture, and durability. Wood is largely composed of carbon, which accounts for the readiness with which it takes fire and the heat which it gives off when burned. There is also a considerable quantity of water, the exact amount depending upon whether the wood is seasoned or is still green, and even seasoned wood, if it is left lying about in a damp place, will absorb more or less moisture from the atmosphere.

There are two words which are used to describe the wood used for building purposes, namely, timber and lumber. Timber is the name which can properly be applied to any wood which is suitable for structural uses, when the material is in its natural state, before it has been cut down and prepared for the market. Lumber is the word which should be used to describe the timber after it has been cut down and sawed up into pieces ready for use. In practice, the word timber is often used to designate the larger beams of a structure although these beams are ready for use. We will first consider the timber in its natural condition, study its manner of growth, the different classes of trees, the defects which are to be found in this material and their causes, the way in which timber is converted into lumber, and pass on to a consideration of the various kinds of timber, studying the characteristics of each both in its natural state and after it has been prepared for use.