mONIGHT'S is the first of a series of six talks by Professor Turner, who is Professor of Glass Technology in the University of Sheffield, past president and secretary of the Society of Glass Technologists, and a well-known international authority on this subject. In this series he confines himself more or less entirely to utilitarian glass, an aspect of the subject which is scarcely ever dealt with in any popular literature. In his first talk he considers what glass is, the materials of which it is composed, and its various uses.