The system of construction in force among the ancient Egyptians resembles in many respects that of the Greeks. The stones are often placed together with dry joints, and without the employment of any binding contrivance, the masons relying on the mere weight of the materials to keep them in place. Sometimes they are held together by metal cramps, or sometimes--as in the temple of Seti I., at Abydos--by dovetails of sycamore wood bearing the cartouche of the founder. Most commonly, they are united by a mortar-joint, more or less thick. All the mortars of which I have collected samples are thus far of three kinds: the first is white, and easily reduced to an impalpable powder, being of lime only; the others are grey, and rough to the touch, being mixtures of lime and sand; while some are of a reddish colour, owing to the pounded brick powder with which they are mixed. A judicious use of these various methods enabled the Egyptians to rival the Greeks in their treatment of regular courses, equal blocks, and upright joints in alternate bond. If they did not always work equally well, their shortcomings must be charged to the imperfect mechanical means at their disposal. The enclosure walls, partitions, and secondary façades were upright; and they raised the materials by means of a rude kind of crane planted on the top. The pylon walls and the principal façades (and sometimes even the secondary façades) were sloped at an angle which varied according to the taste of the architect. In order to build these, they formed inclined planes, the slopes of which were lengthened as the structure rose in height. These two methods were equally perilous; for, however carefully the blocks might be protected while being raised, they were constantly in danger of losing their edges or corners, or of being fractured before they reached the top (Note 7). Thus it was almost always necessary to re-work them; and the object being to sacrifice as little as possible of the stone, the workmen often left them of most abnormal shapes (fig. 52). They would level off one of the side faces, and then the joint, instead of being vertical, leaned askew. If the block had neither height nor length to spare, they made up the loss by means of a supplementary slip. Sometimes even they left a projection which fitted into a corresponding hollow in the next upper or lower course. Being first of all expedients designed to remedy accidents, these methods degenerated into habitually careless ways of working. The masons who had inadvertently hoisted too large a block, no longer troubled themselves to lower it back again, but worked it into the building in one or other of the ways before mentioned. The architect neglected to duly supervise the dressing and placing of the blocks. He allowed the courses to vary, and the vertical joints, two or three deep, to come one over the other. The rough work done, the masons dressed down the stone, reworked the joints, and overlaid the