Wilkinson, John Gardner: Topographie of Thebes, and general view of Egypt: being a short account of the principal objects worthy of notice in the valley of the Nile, to the second cataracte and Wadi Samneh, with the Fyoom, Oases and eastern desert, from Sooez to Bertenice (London, 1835)

444 RAIN IN UPPER EGYPT. [Chap. VII.

were the Egyptians to this point, that the interstices
of the blocks which form the roofs of the temples,
independent of their being well fitted together and
cemented with a tenacious and compact mortar,
were covered by an additional piece of stone let
into a groove of about eight inches in breadth, ex-
tending equally on either side of the line of their
junction.*

However the partial showers and occasional
storms in Upper Egypt might affect the state of
their painted walls, it was not sufficient to injure
the stone itself, which still remains in its original
state, even after so long a period ; except where the
humidity, arising from earth impregnated with nitre,
has been attracted through its granular texture, as
is here and there observable near the ground at
Medeenet Haboo, and in other ruins of the Thebaid.
But exposure to the external atmosphere, which
here generally affects calcareous substances, was
found not to be injurious to the sandstone of Silsilis,
and, like its neighbour the granite, it was only in-
ferior to limestone in one respect, that the latter
might remain buried for ages without being cor-
roded by the salts of the earth; a fact with which
the Egyptians, from having used it in the sub-
structions of obelisks and other granitic monuments,
were evidently well acquainted.

* I have had occasion to mention this before. It may be seen
on the roof of the inner area of the palace of Remeses III. at
Medeenet Haboo.