When grown, the main stem, either used whole, sawn in two, or quartered, will form one wing of the knee, and the bent branch the other; see figs. _c_, _d_. The dotted lines shew the saw section. Particular attention must be paid to prevent oaks from separating into more than four leaders, and also to train up these leaders a considerable height, without allowing them to divide again, retaining always numerous feeders; thus, when the tree acquires size, {28} many valuable crooks _g_, _h_, _i_, will be formed above the knees. It is necessary, however, to guard against training the branches to too great a height, as, when so, they run much risk of being twisted and torn by high winds. Knees may also be obtained by cropping the top from plants that have side branches similar to _f_, and training these branches for leaders as above directed. In this case, the section, where the top is cut off, must not be too large, and the branches, either two or four, well knotted to the trunk, or the situation sheltered, otherwise the trunk at the section may be split down by the strain of the wind on the new leaders. Also, in healthy growing trees of considerable size, which have spreading tops, and which are not to be cut down for a considerable time, the forester, if he have a good eye, may, by lopping off a few branches here and there throughout the top, throw the greater part of the boughs into condition to become knees, or valuable crooks, when of size. This is of most material consequence to the ultimate value of half-grown oak trees, in open situations, and ought to be particularly studied by the superintendent, as, when allowed to run into very numerous _stemmy_ branches, without direction or curtailment, the top, instead of being ultimately of {29} considerable value as timber, is of none. Directions in writing will scarcely suffice to teach a forester this part of his business; he must consider attentively the knee figures and bends we have furnished, fix them in his memory, and use every eligible means to obtain them. Knees, of all descriptions of oak timber are in the greatest request. We have known them purchased at 7s. per computed solid foot, which, from the plan of measuring, is as much as 10s. per real solid foot. The prevailing inattention to judicious training will continue to occasion the supply of knees to be short of the demand, and thence the price high, provided some change does not take place in the structure of vessels, or iron knees be adopted, which are now sometimes used, or vessels, with the exception of the deck and rigging, be formed of iron altogether, which we have seen do very well in inland navigation.