viewed in the log, to be fit for any purpose where straight timber was required.
It is, therefore, clear that trees do not change or alter their form while young, except in a very slight degree; they appear rather to assume the fairer and more even growth later on, and very gradually. It may possibly be brought about by the matter which forms the zones of each succeeding year's growth contributing to one part a greater and to another a lesser substance of woody layer, as required to develop the fairer growth seen in the matured tree referred to. And hence, if we take a perfectly straight tree, and cut it through the middle longitudinally, we are pretty sure to see the pith running snake-like along its entire length (Fig. 7). Therefore, in timber having much heart-shake, there is certain to be considerable waste in its conversion, especially if we wish to reduce the log into plank and board.
