The construction of the roof is
particularly admirable. First, the chamber is covered in with nine huge
blocks, each nearly nineteen feet long and four feet wide, which are
laid side by side upon the walls so as to form a complete ceiling. Then
above these blocks is a low chamber similarly covered in, and this is
repeated four times; after which there is a fifth opening,
triangular, and roofed in by a set of huge sloping blocks, which meet at
the apex and support each other. The object is to relieve the chamber
from any superincumbent weight, and prevent it from being crushed in by
the mass of material above it; and this object has been so completely
attained that still, at the expiration of above forty centuries, the
entire chamber, with its elaborate roof, remains intact, without crack
or settlement of any kind.

Further, from the great chamber are carried two ventilation-shafts, or
air-passages, northwards and southwards, which open on the outer surface
of the pyramid, and are respectively two hundred and thirty-three and
one hundred and ninety-four feet long. These passages are square, or
nearly so, and have a diameter varying between six and nine inches. They
give a continual supply of pure air to the chamber, and keep it dry at
all seasons.

The Great Gallery is also of curious construction. Extending for a
distance of one hundred and fifty feet, and rising at an angle of 26 deg.
18', it has a width of five feet at the base and a height of above
thirty feet. The side walls are formed of seven layers of stone, each
projecting a few inches over that below it. The gallery thus gradually
contracts towards the top, which has a width of four feet only, and is
covered in with stones that reach across it, and rest on the walls at
either side. The exact object of so lofty a gallery has not been
ascertained; but it must have helped to keep the air of the interior
pure and sweet, by increasing the space through which it had to
circulate.

The "Pyramid Builders," or kings who constructed the three monuments
that have now been described, were, according to a unanimous tradition,
three consecutive monarchs, whose native names are read as Khufu,
Shafra, and Menkaura. These kings belonged to Manetho's fourth dynasty;
and Khufu, the first of the three, seems to have been the immediate
successor of Sneferu. Theorists have delighted to indulge in
speculations as to the objects which the builders had in view when they
raised such