We may look upon the different faces of a wooden building as separate pieces of construction which should be put together upon the ground before being combined with each other. This process, though not always made use of in practice, is at least the most logical method for those who wish to make the best use of their materials. But even when thus put together, one of these single faces has not much more stability than each of its constituent elements. In order to form a rigid and stable whole, the several faces must be allied by reciprocal interpenetration at the angles. It was necessary to call attention once for all to these general characteristics of wooden construction, because we shall hereafter have occasion to examine the forms and motives which stone architecture borrowed from wood in the case of other people besides the Egyptians. We must now determine the particular characteristics offered by the material in Egypt, as they may be learnt in the representations to which we have already referred. [Illustration: FIG. 82.--Elements of wooden construction.] When a wall has to be built of wood so as neither to warp nor give way, it is necessary to make use of a certain number of oblique members. This is one of the elementary rules of the carpenter's art, and to form an idea how it was applied in our own country it is enough to cast an eye over any of the wooden buildings of the middle ages or of the renaissance. The Egyptians were not ignorant of the advantages conferred by the use of these oblique members because they employed them frequently in their furniture; but they seem never to have introduced them into the construction of their buildings. All joints are there made at a right angle. They were probably led to reject oblique lines by their unwillingness to break in upon the simple harmony of vertical and horizontal lines which is the distinguishing principle of all their architecture. Thus self-deprived of a valuable resource, they were driven to the discovery of some other means of giving the required cohesion and stability to their walls. This requirement they thought they had fulfilled in exaggerating the points of connection between the vertical and horizontal members, which were thus brought into more intimate relation than would in these days be thought necessary.[107] The consequence of this was that their wooden buildings presented much the same closed appearance (Fig. 83) as we have already noticed in their stone constructions; and, moreover, as every joint was made at right angles, the pyramidal form was entirely absent. [107] In this respect there is a striking resemblance between Egyptian carpentry (see Fig. 83), and much of the joinery of the modern Japanese.--ED. [Illustration: FIG. 83.--Wooden building (first system), composed by Charles Chipiez.[108]]