ABSTRACT
At the Third International Congress on Soil Mechanics at Zürich in 1953, Karl Terzaghi expressed his regret at seeing that the hopes he had placed in the development of clay mineralogy, and which he had presented fifteen years earlier in 1936 at the First International Congress on Soil Mechanics at Cambridge (USA), had been disappointed. Terzaghi no longer believed that there was any possibility of following this approach to find a rational explanation of the behaviour of clays.
