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

462 THE NEW WORLD OF SCIENCE (1946-51)
techniques for numerical computation and their adaptation to machines, as
well as better techniques for training mathematicians in the application of
numerical methods.ol
The new age of mathematics, electronics, nuclear physics, tracer re-
search, radio propagation, and high polymer research challenged the Bureau
to provide a host of new fundamental physical standards, physical constants,
and standard samples. The Bureau also pursued its work on standards in
more familiar areas, some whose adoption had waited oniy for the end of the
war. Thus 1948, the year that saw international adoption of absolute values
for the electrical units, new photometric units, and adoption of a revised
International Temperature Scale,92 also witnessed, after 30 years of eflort,
the first real agreement on unification of the screw thread standards of Great
Britain, Canada, and the United States. Despite Lend-Lease and the common
border to the north, the screw threads produced in these countries all during
the war differed sufficiently to prevent their interchangeability, causing severe
inconvenience and great economic loss. After 3 years of study, an accord
of unification of the American and British standard systems was signed at
the Bureau late in 1948 by representatives of the American Standards Asso-
ciation and their British and Canadian counterparts.93
The year 1948 also marked the near realization of an atomic basis
for the standard of length. Two decades earlier, the Seventh International
Conference on Weights and Measures had agreed to seek a definition of the
meter in terms of light waves.94 Great interest was, therefore, aroused in
the increased accuracy recently found possible with a new light wave, that
of an isotopic mercury in vapor form. The sharp spectral line of this isotope
of mass 198 (Hg'°5) was first observed in 1942 in the Radiation Laboratory
at the University of California. in 1945 Dr. Meggers obtained a small
quantity of the mercury isotope, distilled from proof gold exposed to neutrons
in a chain-reacting pile, from the atomic pile at Oak Ridge.°5
in precision, reproducibility, and convenience, Meggers found the
wavelength of the green radiation from the mercury isotope far superior to
either the standard meter or the wavelength of the red line of cadmium.
inspection testing of five times as many units in a given time by the same staff. Cement
testing was put on a similar statistical basis (Annual Report 1948, pp. 238, 251; Annual
Report 1949, p. 57).
91
NBS Annual Report 1951, p. 67.
NBS Annual Report 1948, pp. 201—203; Annual Report 1949, p. 14. For the earlier
work, see ch. V, p. 246.
98
NBS Annual Report 1949, p. 10; Annual Report 1951, p. 101; Fortune, 38, 86 (1948).
See ch. VI, pp. 335—336.
No attempt at the reverse process, changing mercury to gold, as the alchemists of the
Middle Ages and as a group sponsored by Scientific American in the 1920's tried, was
considered. See Sci. Am. 132, 80 (1925), and issues of December 1924 and March 1925.