into a short helical coil and the bulb filled with
nitrogen or argon gas.

This development was not accidental and from a scientific point of view
it is not spectacular. It did not mark a new discovery in the same sense
as the discovery of X-rays. However, it is an excellent example of the
great rewards which come to systematic, thorough study of rather
commonplace physical laws in respect to a given condition. Such
achievements are being duplicated in various lines in the laboratories
of the industries. Scientific research is no longer monopolized by
educational institutions. The most elaborate and best-equipped
laboratories are to be found in the industries sometimes surrounded by
the smoke and noise and vigorous activity which indicate that
achievements of the laboratory are on their way to mankind. The
smoke-laden industrial district, pulsating with life, is the proud
exhibit of the present civilization. It is the creation of those who
discover, organize, and apply scientific facts. But how many appreciate
the debt that mankind owes not only to the individual who dedicates his
life to science but to the far-sighted manufacturer who risks his money
in organized quest of new benefits for mankind? A glimpse into a vast
organization of research, which, for example, has been mainly
responsible for the progress of the incandescent lamp would alter the
attitude of many persons toward science and toward the large industrial
companies.

The progress in the development of electric incandescent lamps is shown
in the following table, where the dates and values are more or less
approximate. It should be understood that from 1880 to the present time
there has been a steady progress, which occasionally has been greatly
augmented by sudden steps.

APPROXIMATE VALUES

Lumens per
Date Filament Temperature watt
1880 Carbon 3300 deg.F. 3.0
1906 Carbon (graphitized) 3400 4.5
1905 Tantalum 3550 6.5
1905 Osmium 3600 7.5
1906 Tungsten (vacuum) 3700 8.0
1914 Tungsten (gas-filled) up to 5300 deg.F. 10 to 25

Throughout the development of incandescent filament lamps many ingenious
experiments were made