242 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1912. 



In the metal filament lamp industry, tungsten, which shows the 

 highest melting pomt of all metals, namely 3,100°, has replaced 

 tantalum, which melts at about 2,300°. This became possible 

 only after successful experiments to render the metal ductile by 

 hammering. 



The elements cadmium, selenium, and tellurium are obtained in 

 great quantities as by-products; the first is produced m the zinc 

 industry, the other two from the Tellur gold ores which are found 

 in Cripple Creek, Colo. Although they are sold at relatively low 

 prices they find but little use in the industries. 



ARTIFICIAL PRECIOUS STONES. 



Finally, I wdl, in but a few words, touch upon a new industr}^, 

 Viz, the synthetic manufacture of precious stones from alumina with 

 additions of chrome oxide, iron oxide, or titanic acid. Artificial 

 rubies and white, yellow, and blue sapphires, which can not be dis- 

 tinguished from natural stones, are bemg manufactured in great 

 quantities in Paris and recently also by the Electrochemische Werke, 

 Bitterfeld. They are used extensively for jewelry and especially as 

 bearings in watches and measuring instruments. 



.All this will give you a striking picture of the development of inor- 

 ganic chemistr}^, which is taking a more and more important position 

 beside organic chemistry. 



APPLIED ORGANIC CHEMISTRY. 



In the organic chemical industry the reactions are considerably 

 more comT)licated and the apparatus mostly smaller than in the 

 inorganic industry. Here the chemist, like a juggler with his balls, 

 gives every atom a definite position in the many thousand combina- 

 tions which carbon forms with hydrogen, oxygen, nitrogen, and sul- 

 phur, and there exist the most varied reactions and processes which 

 may lead to the same result. This chemistry of the carbon com- 

 pounds has been most wonderfully perfected in the coal-tar color 

 industry, and in every factory of this branch there are hundreds of 

 scientifically trained chemists always experimenting and daily finding 

 new combinations possessing properties of technical value. Before 

 these products become finished articles to be sold as colors, perfumes, 

 or pharmaceutical preparations they must further go through a series 

 of munerous intermediary operations, which finally lead to the mar- 

 ketable chemicals. 



COAL TAR. 



The starting material of the important coal-tar color industry is 

 tlie black tar Avhich is obtained by the dry distillation of coal and is 

 known to contain about 150 different chemical products, of which, 



