A cause of 'intense alarm and distress' (1904)


On some disregarded points in the stability of masonry dams. Drapers' Company research memoirs. Technical series, II.

Published: London, Dulau and Co.

Date: 1904

4to (300 × 230 mm), pp. 27; two folding plates; ex-libris of City & Guilds College to front pastedown, with a number of library stamps throughout the text; very good in contemporary brown cloth, title gilt to upper board, library markings to spine.

COPAC shows five copies in UK institutions, at the BL, Oxford, Cambridge, Manchester and the National Library of Scotland.

First edition of Atcherley and Pearson's challenging and 'alarming' work on the stability of masonry dams. 'An interesting postscript to the story of [George] Deacon and the Vyrnwy works was started in 1904 by the publication of a memoir “On Some Disregarded Points in the Stability of Masonry Dams” by L. W. Atcherley and Professor Karl Pearson. This postulated – very reasonably – that, if engineers were accustomed to consider the forces acting on horizontal sections, then they should do the same on vertical sections. The memoir went on to show how a horizontal tension could theoretically occur near the air face, at the bottom of the dam. Some crude experiments with wooden models supported their thesis that, "The current theory of the stability of dams is both theoretically and experimentally erroneous." 'This memoir caused intense alarm and distress among civil engineering circles, as was evidenced by the decision in March 1905 to postpone, if not abandon, the raising of the Aswan Dam. A lively correspondence ensued in the columns of Engineering in which Professor Unwin played a leading part, but it seemed impossible to prove that Pearson was wrong. On 31 January 1908 three papers were presented for discussion at the Institution of Civil Engineers. The first, by Sir John Ottley and A. W. Brightmore, of whom the latter had been Deacon's pupil and Resident Engineer on the Mersey Crossing, described experiments on plasticine models. 'The second paper, by J. S. Wilson and W. Gore, was an excellent account of experiments to determine stresses in dams by means of india-rubber models, which represented a section of the dam with its foundations … This paper received high praise from those present because it convincingly and finally removed all the doubts which Pearson had sown. Deacon drew attention to the remarkable ingenuity by which the virtual density of the model was increased. The use of ellipses of stress was, he believed, quite new. Of supreme importance was the tension at the upstream toe. It was necessary to consider the foundations with the dam.' (I. Davidson, 'George Deacon (1843-1909) and the Vyrnwy Works', Transactions of the Newcomen Society, 59 (1987): 81-95, at 91) Karl Pearson (1857-1936) is better known for his work in statistics, elasticity theory, and even more so for his controversial (and sometimes explicitly racist) views on the relationship between Darwinian evolution and eugenics. Here Pearson was as controversial as ever, and caused great consternation for several years before his predictions were proven to be unfounded. Also see Timoshenko, History of strength of materials, pp. 343-344.

Very good