HOW THE PYRAMIDS WERE BUILT

Sun (Auckland), Volume III, Issue 759, 4 September 1929, Page 2

HOW THE PYRAMIDS WERE BUILT

For information regarding the instruments used in the laying out of the great constructional works of antiquity we are mainly indebted to the writings of Hero of Alexandria and of Marcus Vitruvius Pollio, both of whom lived In the first century, 8.C.. and to Sextus Julius Frontinus, the famous writer on Roman aqueducts, who died about A.D. 10G. Euclid, Archimedes, Eratosthenes, Appollonius and other great mathematicians of the first Alexandrian School had long since passed away, but they had left behind them the classical works in geometry and astronomy containing those fundamental discoveries on which, practical surveying is based, says a correspondent in “Engineering.” How successfully the principles were applied can be seen by the roads, canals, sewers, tunnels, harbours, reservoirs and aqueducts, the remains of which today testify to the accuracy, perfection and grandeur of the work of the civil engineers of those times. Yet long before Hero and Vitruvius, there had been great constructors. In Egypt, in 3.700 8.C.. there existed a “Superintendent of Works,” who had charge of the construction of public edifices and roads, and the Pyramids stand as a monument to the ingenuity and skill of long-forgotten designers. The Great Pyramid is estimated to have a mass of over 6,000,000 tons of stone. Its base is 7G4 feet square, yet in the four sides there is only a mean error of 6-lOin. in length and 12 seconds in angle from a perfect square. How this accuracy was obtained we do not know, and we have to wait until much later times for the description of instruments from which our own have been developed.

An account of the ancient field instruments used l»v the Greeks and Romans was given by Mr. R. C. S. Walters in a paper to the Newcomen Society in 1921. and last year Mr. E. N. Stone added further to our knowledge by his interesting pamphlet oq “Roman Surveying Instruments/' published by the University of Washington Press, Seattle. This pamphleC forms a part of Vol. 4 of the University of Washington Publications in Language and Literature. Mr. Noble has been at some pains to go to the original authorities, Hero, Vetruvius and Frontinus, and deals in turn with instruments for determining the true meridian, for linear measurement. for measuring horizontal and vertical angles, and with levelling instruments. Roman surveyors depended on the sun to give them their true bearing, and the two devices, the sundial and the gnomon, both of which are generally credited to Anaximander, who lived in the sixth century. B.C'., were in common use. It is Vitruvius who gives full directions as to the method to be employed in constructing them and setting them up. and who calls attention to the fact that a dial can be accurately set only by taking the equinoctial shadow. By * the dial, the four or eight principal points of the compass could be determined, and from these the architect could lay out the streets and alleys so that “the disagreeable force of the winds will be shut off from the dwellings and blocks.” One of the most interesting buildings still standing in Athens, and illustrating this determination of the eight points of the compass, is the Tower of the Winds of Andronicus Cyrrhestes. It is octagonal in form, and beai'3 figures representing the characteristics of the winds to which they were inscribed. The building was surveyed by Stuart and Revett; Delambre speaks of it as “the most curious existing monument of the practical gnomonics of antiquity,” and. in a sense, it may be regarded as the oldest meteorological station In ,he world.