Construction by Assemblage. i i 5 buildings of the less durable material. The constructive principles which we have next to notice, have thus left traces behind them which will enable us to describe them with almost as much accuracy as if the carpenters of Cheops and Rameses were working before our eyes. We need not insist upon the characteristics which distinguish assembled construction from masonry or brickwork. The different parts of the former are, of course, much more intimately allied than in buildings constructed of large stones. Supports of dressed stone truly fixed with the plumb line are perfectly stable of themselves. In both Egypt and Greece we often come upon a few columns still standing upright amid their desolate surroundings, and announcing to the traveller the site of some city or famous temple which has been long destroyed. But wooden supports have little thickness in comparison with their height, and the material of which they are formed, being far less dense than stone, cannot maintain itself in place by its own weight. It is the same with wooden architraves. The heaviest beams of wood will not keep their places when simply laid one upon another, and are in that matter far inferior to those well dressed stones which, in so many ancient walls, have resisted change with neither tenons nor cement to help them. As a general principle, when wood has to be employed to the best advantage, and endowed with all the solidity and resisting power of which it is capable, the separate pieces must be intro- duced one into another (Fig. 82). But even when thus combined and held in place by mechanical contrivances, such as bolts and nails, they will never form a homogeneous and impenetrable mass like brick or stone. By such methods an open structure is obtained, the voids of which have afterwards to be filled up by successive additions, and these additions often take the form of what we call panels. 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 pro- cess, 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
