8
A HISTORY OF ENGINEERING
mile, for transporting the blocks brought down the Nile from the "Arabian Mountain." He also mentions that ten years were spent in making this road, which, in his opinion, was a hardly less notable work than the building of the Pyramid itself. An excellent illustration of the engineering skill of the Egyptian people is afforded by their methods of quarrying, transporting, and erecting the huge blocks of stone used for obelisks. In order to separate the huge blocks of stone from the native rock, a groove was cut to mark the outline of the stone required, into which groove frequent holes were bored for the insertion of wooden wedges. When the wedges had been firmly secured in place, the groove was filled with water, which caused the wooden wedges to swell and crack the granite throughout the length of the groove. Rollers made from the branches of palm-trees were used to push the stone forward to the banks of the Nile, where it was surrounded by a timber raft. With the rising waters of the Nile the raft floated and carried the obelisk to the point on the river where it was to be set down. Thousands of labourers then dragged the stone and pushed it on rollers up an inclined plane, where by the use of levers and ropes made of the date-palm, the obelisk was placed in its final upright position. " It speaks much for the mechanical accuracy of the Egyptian masons that so true was the level of the top of the base and the bottom of the long shaft that in no single instance has the obelisk been found to be out of the true perpendicular."* Similar methods of transporting and lifting huge blocks of stone are to-day used by primitive tribes —for instance, the Khasi hill tribes of India, who still erect megalithic monuments. " The slabs of sandstone are quarried near by where they are to be set up by means of wedges. Some of these weigh twenty tons. They are moved on a cradle made of strong limbs of trees, roughly smoothed and rounded so as to present little surface to friction. In dragging and setting up the slabs, all the members of a community are under an obligation to assist on such an occasion, and are not paid for their labour, receiving in the evening a little food or liquor at the dwelling of the family who sought the aid."f * King, Cleopatra's Needle, 18. f Austen, Journal Anthrop. Institute
(1872), I. 127.
FUNDACION JUANELO TURRIANO