Control of Seepage through Foundations and Abutments of Dams

Abstract

I am deeply grateful to the members of the British National Committee for the great honour of inviting me to be your first Rankine Lecturer. The name Rankine was, of course, familiar to me in my student days. In my mind I had classified him in the same category with such eminent German engineers and teachers as Otto Mohr, Müller-Breslau, and Föppl. But until recently I had no conception of the enormous breadth and depth of Rankine's contributions in several areas of engineering as well as in pure science. And all this he accomplished in his short life span that I have exceeded already by 6 years. I could easily use the entire hour to talk about my impressions when reviewing Rankine's books and scientific papers. But may I mention just one item that concerns the conflict between theoretical science and engineering, a topic often discussed at the present time particularly in the United States where we are undergoing a period of critical review of engineering education and are groping for something new that nobody seems to be able to define clearly. As always in periods of uncertainty, there is a tendency to be over critical of past efforts; there is a danger of “throwing the baby out with the bath water”—at least that is the impression I have about certain changes which are being attempted in the teaching of civil engineering at some of our schools. Let me read two short paragraphs that bring out in essence what Rankine thought about this conflict that seems to have already existed in his days. My quotation is from his inaugural address when he accepted the professorship at the University of Glasgow, in 1856. This is what he said more than 100 years ago: “In theoretical science, the question is—What are we to think?—and when a doubtful point arises, for the solution of which either experimental data are wanting, or mathematical methods are not sufficiently advanced, it is the duty of philosophic minds not to dispute about the probability of conflicting suppositions, but to labour for the advancement of experimental inquiry and of mathematics, and await patiently the time when these shall be adequate to solve the question. “But in practical science the question is—What are we to do?—a question which in volves the necessity for the immediate adoption of some rule of working. In doubtful cases, we cannot allow our machines and our works of improvement to wait for the advancement of science; and if existing data are insufficient to give an exact solution of the question, that approximate solution must be acted upon which the best data attainable show to be the most most probable. A prompt and sound judgement in cases of this kind is one of the characteristics of a PRACTICAL MAN, in the right sense of that term.” This is, indeed, the best definition of the difference between theoretical science and engineering I have been able to find. Also, it serves as an admirable introduction to the subject of my Lecture in which I will make use of theory to supplement empirical knowledge and to enhance “sound judgement”.