198 Soon you don't hardly notice all this waste heat, Sir! But it is the urgent business of Management to turn all low-grade heat to good account. Have you any engine exhaust steam ? Flash steam, process vapour, hot exhaust air, spent hot water, or hot process liquors? The Ministry Bulletins tell you in detail how to set one and all to useful work. The result is fuel economies like the following :— AN ARTIFICIAL SILK FACTORY used to humidify the air—400,000 cubic feet a minute of it— by injecting live steam into water sprays.