0NE of the problems of civilisation to-day is the prevention of waste, and most countries of the world, if they adopted scientific methods, could live on what they throw away. One good example of this is the fact that millions of tons of ash and clinker, from steam boiler, destructor and other furnaces, for example, together with blast furnace slag, are wasted every year, whereas all this material could be converted, at a handsome profit, into high grade bricks.
A Correspondent