n

HISTORY OF ENGINEERING.

Book I,

headed wooden mallet and chisel, we have no difficulty in accounting for the fine surfacesand the nicely made joints which the stones in some instances present to us; and thecauseway extending in length more than 3000 feet, with a breadth of 60, and height of48 feet, we can also imagine the same facilities for the transport of materials were con-trived and adopted as by us at the present day. Herodotus says, “that when the Great Pyramid was designed, that the workmen might more easily move the stone, this cause-way, which is contiguous to it, was formed : its length was five stadia, its breadth tenorgyes, and its height eight.” This was not the causeway seen by Pocoeke, the length ofwhich he traced for upwards of 1400 feet, after which it was buried in the alluvial depositof the inundation. It was, at a later time, — probably when used by the caliphs and Mem-look kings to carry away the stones for the construction of the several mosques they raised,— repaired and strengthened by sixtv-one circular buttresses, placed about 30 feet apart,and each having a diameter of 14 feet.

The causeway mentioned by Herodotus still remains in part, and reached to the westside of the canal which communicated with the Nile ; and hence the blocks of stone,brought from the east side of the Nile , were easily moved along this inclined plane, to thelevel platform where they were required for the easing of the pyramid.

The base of the Great Pyramid is a square of 764 feet. This measurement was takenby M. Jomard, on the side to the north, after digging down to the true base; and the totalperpendicular height was also found by him to have been 479 feet. Since that period,Mr. Perring has given us the following dimensions, from accurate measurement: —

The former baseTlie present do.

Perpendicular heightFormer inclined height -Present do. -

Perpendicular height by casing stones

764ft. Oin.746 0

450 9

611 0568 3

480 9

The total area of the base was 13 acres, 1 rood, 22 poles, and at present it covers12 acres, 3 roods, and 3 poles. And supposing the rock to average 8 feet in heightonly over the whole extent of base, after deducting the hollow passages and chambers,Mr. Perring calculates that the quantity of stone originally used amounted to 89,028,000cubic feet, or about 6,848,000 tons.

The present quantity of masonry, supposing it solid, is about 82,111,000 cubic feet, or6,316,000 tons; the space occupied by the chambers and passages being taken at 56,000cubic feet. Dr. Clarke observes that the stone used was a grey limestone, and rathermore compact than that called clunch, and that when it was struck with a hammer itexhaled a fetid odour. Denon describes this pyramid to have had 208 courses in height.

The outside casing stones were found (Jig . 9.), at the bottom, in their original position,

l*r( AV" r, .._ n !

fig. 9.

near tne centre ; they were quite perfect, and had been hewn to their required angle beforethey were built in, and appear to have been afterwards polished down to one uniformsurface. They were cut to an angle of 51° 50^ and were in height 4 feet 11 inches.At the base they measured 8 feet 3 inches, and on the inclined side 6 feet 3 inches. "Wherethey were jointed, the cement which interposed was so remarkably fine a layer, that itwas scarcely perceptible.