November 26, 1915] 



SCIENCE 



739 



petroleum or natural gas; and chemistry 

 again lias shown how wastes may be avoided 

 and by-products utilized. The great losses 

 formerly permitted in the coking of coal 

 are now being checked and the volatile 

 products recovered, with the result that we 

 shall soon be supplying all the benzole 

 needed for our own home market. In the 

 great illuminating gas industry, the by- 

 products — ammonia water, tar and coke — 

 are all made available by the chemist. The 

 ammonia water is a leading source of am- 

 monium compounds ; and, as for the tar, the 

 way in which this black, sticky, evil-smell- 

 ing mass has been made to minister to the 

 comfort and general prosperity of mankind 

 constitutes one of the most brilliant chap- 

 ters in the volume of modern scientific 

 achievement. In the hands of the chemist, 

 it has been transformed, as by magic, into 

 a veritable Pandora's Box, from which may 

 be produced healing drugs or the deadliest 

 of poisons, delicious perfumes or the most 

 disgusting of odors, dyestuffs of every hue 

 of the rainbow or explosives powerful 

 enough to annihilate this building in an 

 instant — pleasure or pain, life or death, lie 

 dormant there, awaiting the summons of 

 the chemist. Then, too, chemistry has con- 

 tributed the necessary mantles and fila- 

 ments for modern incandescent lighting, 

 whether by gas or by the electric current; 

 and the calcium carbide from which acety- 

 lene gas is obtained. 



A good example of the economy often 

 accomplished by chemical research and dis- 

 covery is afforded by the history of ultra- 

 marine. Many years ago when this pig- 

 ment was made by powdering the mineral 

 lapis lazuli, it sold for more than its weight 

 in gold. Since the chemist has found how 

 to make it from such cheap substances as 

 kaolin, sodium sulfate and carbonate, char- 

 coal, sulfur and rosin, the price is only a 

 few cents per pound. 



The value of our specie, upon which every 

 conunercial transaction rests, is decided by 

 the chemist, while the green ink used in 

 printing our banknotes, and to which they 

 owe their name of "greenbacks," was in- 

 vented by a former president of the Amer- 

 ican Chemical Society, Dr. T. Sterry Hunt. 



The chemist lets nothing escape un- 

 searched. The sweepings from the mints 

 and from the shops and factories of workers 

 in precious metals, as well as the water in 

 which the workmen wash their hands, are 

 all made to give up the gold or silver they 

 contain. Even waste photographic solu- 

 tions must disgorge their silver before they 

 are permitted to escape. 



Through the labors of the chemist, the 

 pollution of our atmosphere by smoke, 

 fumes, flue dust and noxious gases is being 

 rapidly reduced; and the University of 

 Pittsburgh is playing a prominent part in 

 this campaign. Hundreds of thousands of 

 tons of sulphur dioxide, formerly wasted 

 in various quarters of the globe in polluting 

 the atmosphere, are now, thanks to the dis- 

 covery of the "contact process," annually 

 converted into sulphuric acid, to be used 

 for the manufacture of fertilizers, indigo 

 and other valuable substances. 



The purity of our water supply is a mat- 

 ter of serious concern to all of us, whether 

 it is to be used for drinking purposes or for 

 the industries, and both the chemist and the 

 bacteriologist must pass upon it. The chief 

 industrial use of water is for the genera- 

 tion of steam, and for this purpose the 

 water must be free from large amounts of 

 mineral salts, or the formation of boiler 

 scale will proceed rapidly. So that, even 

 in such a fundamental engineering opera- 

 tion as steam-power generation, the engi- 

 neer must first 'consult the chemist as to the 

 quality of the fuel and water he expects to 

 use. The loss due to locomotive boiler scale 

 alone in the United States has been esti- 



