in works, and must mould his solution of the problem to harmonise with these possibilities. The undertaking is often more complex than that of the pure scientist. It is one which needs a special laboratory, a special equipment.
As examples of such a laboratory, both of which happen to be at works, I may instance the Research Laboratory of the Badische-Anilin-Soda-Fabrik, in which the commercial production of synthetic indigo was worked out, or the laboratory of the General Electric Co. of America at Schenectady, where in numerous instances the discoveries of modern electrical theory have been turned to practical use. The Coolidge tube, the most powerful source of X-rays which we possess, is one product of this laboratory. Other examples are some branches of the Bureau of Standards at Washington, the Materialprüfungsamt at Gross-Lichter-
