# The Surface of the Earth as a Material of Construction. Discussion on Mr. H.H. Leys's Paper

*The CHAIRMAN (Mr. Ewart Andrews) said that he was sure all those present had enjoyed the paper, and, when they had studied it sufficiently well to understand it, they would realise that Mr. Leys had spent a great deal of time and thought in tackling this paper on the very difficult subject that the Americans, he thought, called "soil mechanics.” Mr. Leys had said in connection with one of the diagrams, that Rankine had
assumed that a certain line was a straight line. The fact was that he had assumed it was a straight line because that made if easy for him to get his formula! That, indeed, was the reason for all these mathematical assumptions. If one did not make some assumption which enabled a certain simple result to be reached, then, of course, one could not get anywhere. *