Measures for Progress: A History of the National Bureau of Standards

112 ELECTRICITY, RAILROADS, AND RADIO (1911-16)
of light, for use in pyrometrical measurement. For lack of suitable materials
at that time, 20 years passed before the work was resumed and an absolute
prototype standard was at last experimentally realized. With it the incandes.
cent lamp standard, always difficult to maintain, was reduced to a working
standard.
A uniform sitandard of light was not enough to assure acceptance of the
lamps made by the electric industry, and 2 years before adoption of the inter-
national candle representatives of the lamp manufacturers in this country
met with Government engineers at the Bureau to adopt standard specifica-
tions for electric lamps. Although the General Electric Co. had introduced
its G.E. metalized (GEM) carbon-filament lamp in 1905, and in 1907 put
its first tungsten.filament (Mazda) lamp on the market, the first specifica-
tions were based on the Edison carbon.filament lamp, then owned and manu-
factured by General Electric and its subsidiaries and the most widely used
of electric lamps available.
It was agreed that the carbon-filament lamps sold to the Govern.
ment must initially consume no more than 3.76 watts per mean spherical
candle (the Bureau standard) and their "life," before decreasing to 80 per.
cent of their original light value or burning out, must be 300 to 450 hours.
Failure of 10 percent of the test lamps in any lot would automatically result
in rejection of the entire lot. The details of these specifications were pub.
lished in NBS Circular 13 (1907) and revised editions of the circular ap.
peared with the adoption of the international candle and as each of the new
types of electric lamps came into general use.18
Although Bureau testing of incandescent lamps was the entering
wedge, it was not by electric light but by old-fashioned gas light that the
Bureau prepared its first proposals for the regulation of a public utility.
For years the illuminating gas and oil industry had referred to Hefner and
pentane lamps for its photometric standards. How unreliable these stand-
ards were the Bureau learned in 1906 when some 40 kerosene oils were sub-
mitted to it for tests of their composition and illuminating power.19
Preliminary studies revealed the necessity of a thorough investiga-
tion of gas and oil illuminants, and in 1908 the Bureau requested and re-
ceived from Congress a special 2-year appropriation to work on this problem,
in cooperation with the American Gas Institute. Russell S. McBride, a
bright young graduate in chemistry from the University of Wisconsin, was
brought into Rosa's electrical division, sent to school for courses in gas engi-
neering, and put in charge of the investigation.20
18 The last edition of C13, "Standard specifications for incandescent electric lamps," was
the 10th, in 1923, after which the Federal Specifications Board, recently established in
the Bureau of the Budget, took over the function of promulgating lamp specifications.
Hearings * * * 1907 (Feb. 23, 1906), p. 653.
20 See Hearings * * * 1915 (Feb. 26, 1914), p.910.