Correspondence

THIS3 question of density when relating to concrete for all purposes, and particularly when the concrete is to withstand a hydrostatic pressure, is all important to the engineer, and hence it is no wonder that he is tempted to administer “patent medicines” to the concrete when he has doubts as regards its “bodily fitness.” Alfred S. Grunspan

THE cost of grinding the raw materials, coal and finished cement is a considerable proportion of the total cost of cement manufacture. With a view to reducing this cost of grinding, the British Portland Cement Research Association has carried out a comprehensive research dealing with some of the fundamental principles governing the crushing of materials used in cement manufacture to a greater degree of fineness. Chas E. Blyth, Geoffrey Martin and Harold Tongue

The treatment of concrete surfaces with siicate of soda is by no means a new process. Until quite recently it has been confined to the treatment of factory floors to prevent dusting, and the best results have not been contained consistently because the grade of silicate of soda used has been unsuitable and the methods of application have not been properly studied. L.A. Munro