Properties Long Deemed Useless are Now Gainful.
If properties at first unwelcome have at last been turned to account, so also have properties which were long deemed utterly useless. A big and interesting book might be filled with the story of how by-products, long thrown away as worthless, have rewarded careful study with great profit. Thus for ages was bran discarded in flour-mills: to-day it may afford all the miller’s profit, or even more than that profit. In the Southern States until a generation ago cotton seed was regarded as valueless. At present that product, so long wasted, is the basis of a great industry, a ton of seed yielding about 1089 lbs. of meat to 20 lbs. of lint; out of this meat 800 lbs. are cake and meal; the remainder, 289 lbs., forms an oil which furnishes a substitute for olive oil and lard. Until a few years ago glycerine was thrown away as produced in candle-works and soap factories. It is now so valuable that manufacturers adopt just that method of preparing fatty acids which yields most glycerine from neutral fats. So in paper-making, the soda which formerly was sent into creeks and rivers to the pollution of sources of water-supply, is now used over and over again, largely increasing the net results of manufacture. No industry has shown of late years so large utilization of products formerly wasted as the iron and steel manufacture. Its slags are made into bricks, cement, and glassy non-conductors of heat and electricity. Its gases are used for engines developing immense motive powers, or they are in part condensed for valuable acids or other compounds. In these cases and thousands more the question has been, What are the properties of these by-products? How can they be made useful?