courses of
carefully adjusted blocks to form a substructure, the Nile was ever
threatening them, and secretly working at their destruction. Its waters,
filtering through the soil, were perpetually in contact with the lower
courses of these buildings, and kept the foundations of the walls and
the bases of the columns constantly damp: the saltpetre which the waters
had dissolved in their passage, crystallising on the limestone, would
corrode and undermine everything, if precautions were not taken. When
the inundation was over, the subsidence of the water which impregnated
the subsoil caused in course of time settlements in the most solid
foundations: the walls, disturbed by the unequal sinking of the ground,
got out of the perpendicular and cracked; this shifting displaced the
architraves which held the columns together, and the stone slabs which
formed the roof. These disturbances, aggravated from year to year, were
sufficient, if not at once remedied, to entail the fall of the portions
attacked; in addition to this, the Nile, having threatened the part
below with destruction, often hastened by direct attacks the work of
ruin, which otherwise proceeded slowly. A breach in the embankments
protecting the town or the temple allowed its waters to rush violently
through, and thus to effect large gaps in the decaying walls, completing
the overthrow of the columns and wrecking the entrance halls and secret
chambers by the fall of the roofs. At the time when Egypt came under
the rule of the XIIth dynasty there were but few cities which did not
contain some ruined or dilapidated sanctuary. Amenemhait I., although
fully occupied in reducing the power of the feudal lords, restored; the
temples as far as he was able, and his successors pushed forward the
work vigorously for nearly two centuries.

The Delta profited greatly by this activity in building. The monuments
there had suffered more than anywhere else: fated to bear the first
shock of foreign invasion, and transformed into fortresses while the
towns in which they were situated were besieged, they have been captured
again and again by assault, broken down by attacking engines, and
dismantled by all the conquerors of Egypt, from the Assyrians to the
Arabs and the Turks. The fellahin in their neighbourhood have for
centuries come to them to obtain limestone to burn in their kilns, or to
use them as a quarry for sandstone or granite for the doorways of their
houses, or for the t