In the case of elm and young ash the sapwood is, however, superior to the heart. The heartwood is usually harder and more durable than the sapwood, heavier, of better texture, and commonly of better colour.
"The sapwood is, as a rule, darker in the whitewood class than the heartwood, whether seasoned or unseasoned, but is paler in colour in most hardwood trees which have had time to season. In some of the white, or softer woods, when fresh cut, the difference is scarcely perceptible; but exposure to the air quickly gives to the outer layers a greenish tinge, due to a species of mould fungi which attack them."—Laslett and Ward. (See also [Appendix].)
When buying, do not take boards just as they happen to come from the pile. Select them yourself. Most good-natured dealers will let you do this if you do not expect them to unstack a whole pile just for one or two boards. It is better to do this for nice work even if a slight charge should be made for the privilege. When you come to pick out boards you will see the application of what has been said about the ways of cutting the log, and you can tell by the annual rings at the ends of the boards, by the sapwood (when visible), the grain, etc., from what part of the log the pieces were sawed.
Use good, clear stock for everything but rough work. Of course in rough or temporary work you can save expense by using wood from packing-cases, boxes, old fence-rails, or anything that will serve the purpose, but as a rule avoid trying to make nice, new things of wood taken from old work or boxes. The quality of the wood used for boxes nowadays is apt to be poor and hard to work. The wood taken from old cabinet-work is, however, often better than you are likely to buy, but you need to be very cautious about working over old material, for the dirt which has been ground into it is apt to dull your tools, and, moreover, the presence of concealed nails, etc. (which it is sometimes almost impossible to detect), will often injure your tools so much as to more than offset what you save in expense.
Do not buy thick stock with the idea of sawing it into thinner pieces (unless necessary). Of course it can be sawed into thinner or smaller pieces, but you cannot always be sure that these will be as true as the original stock. Suddenly exposing the middle of a piece of wood to the air in this way sometimes plays queer pranks with the shape of the pieces (see [Appendix]). If you want to use boards for good work buy those which have seasoned as boards, instead of splitting up thicker lumber; and always try to treat both sides of a board alike so far as you can.
Bear this in mind: If you take an inch board to the mill to be planed down to three eighths of an inch, for instance, have it planed equally, as nearly as may be, from both sides. Ignorant hands often simply smooth off, or "surface," one side, and then plane the board down on the other side, when it will sometimes warp badly at once and be useless, perhaps, for the purpose intended.
If you carefully pile and "stick" the stock you have bought (Fig. 28), it will tend to keep the pieces straight and true. Never lay good boards down flat directly upon one another unless they are thoroughly seasoned. It is the best of all ways, however, to keep a pile of thoroughly seasoned stock, but not the way to season it. The top board will warp. Never lay a single board of nice stock flat on its side. Keep short pieces of nice stock standing on end where they will be equally exposed on both sides to heat and cold, moisture and dryness.
The best way to learn about any kind of wood is from the wood itself. It is a capital idea to make a collection of specimens of as many kinds as you can.[12] You will be surprised to see how varied, interesting, and handsome a collection you can make at little or no expense. (See [Appendix].)