Heyerdahl, Thor, Aku Aku, London, 1958, 150–151.
That is, broadly speaking, ‘leverage’. A rigid lever on which the load rests at 1-5 ft. from the fulcrum on one side, and the effort is exerted at 1.5 ft. from the fulcrum on the other, gives a mechanical advantage of 10 (i.e. 15 ÷ 1.5), and allows the lifting of, say, 500 lb. by an effort of 50 lb. To counterbalance this gain, of course, the effort must be exerted through ten times the distance that the load is lifted.
The maximum downward pull or push that a man can exert on a lever is of course equal to his own weight, or say 150 lb. But with his feet off the ground he can exert no control. I therefore assume here a maximum effort of 100 lb. per man.
Singer, Holmyard and Hall, , ed., A History of Technology, I, 1954, 735, fig. 535.
Proc. Prehist. Soc, 1959, 280; ibid., 1960, 349.
As a first approximation I have arrived at the empirical formula H = V(120 + 8L + 2F)/1000, where H equals the total man-hours required, V is the volume of solid chalk excavated in cu. ft., and L and F are respectively the vertical and horizontal distances in feet between the centroids (the ‘centres of gravity’) of the cross-sections of the ditch and bank as originally constructed. I shall be glad to discuss the derivation of this formula with any interested reader.
Mathematical Gazette, XLV, 1961, 83-93.
Grimes, W. F., Excavations on Defence Sites, 1939-45, I, 1960, 149, fig. 60.
ANTIQUITY, 1949, 32, fig. 1.
Re-excavated and restored for the Ministry of Works by the writer in 1960 and 1961. Report to appear in Archaeologia Cambrensis.
I owe this observation to Professor Stuart Piggott, whose report on the site is in the press.
e.g. the Dorset Cursus (ANTIQUITY, 1955, 9) and the Benson (Oxon.) Cursus (Ant. Journ., XIV, 1934, 414. pl. LVII).
e.g. that at Benson cited above, and the neighbouring site at Sutton Courtenay (Berks.), ibid., pl. LVIII.
Such an arrangement is illustrated by Dr
Hope-Taylor, Brian in National Geographic Magazine, 117, 1960, 850–851.
For diagrammatic illustrations of the processes described below, see Stonehenge and Avebury, H.M.S.O., 1959, 62.
ANTIQUITY, 1957, 228-233.
See on this
Atkinson, R. J. C., Stonehenge, Pelican, 1960, 134–139.