10 feet; at Luxor, on the side anciently washed by the river, three courses
of masonry, each measuring about 2-1/2 feet in depth, form a great platform
on which the walls rest; while at the Ramesseum, the brickwork bed on
which the colonnade stands does not seem to be more than 10 feet deep.
These are but slight depths for the foundations of such great buildings,
but the experience of ages proves that they are sufficient. The hard and
compact humus of which the soil of the Nile valley is composed, contracts
every year after the subsidence of the inundation, and thus becomes almost
incompressible. As the building progressed, the weight of the
superincumbent masonry gradually became greater, till the maximum of
pressure was attained, and a solid basis secured. Wherever I have bared the
foundations of the walls, I can testify that they have not shifted.

[Illustration: Fig. 52.--Masonry in temple of Seti I. at Abydos.]

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