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

STANDARDS FOR THE AGE OF ELECTRICITY 109
In 1929 the International Committee of Weights and Measures at
Sèvres, to which the establishment and conservation of electrical standards
had been assigned in 1923, approved a resolution to replace the international
system of electrical units by the absolute or CGS system originally proposed
for them. The need for conveniently reproducible standards had diminished
with the expansion of testing services in the national laboratories. Elec-
trical methods of measurement, of increasing importance to science and engi.
neering, demanded higher and higher degrees of precision that apparently
only an absolute system of measurement could satisfy. Also the discovery
of isotopes in 1913, with their hitherto unsuspected variation among different
samples of silver and mercury reduced the certainty of international units
defined by properties of these elements and favored absolute units independ-
ent of isotopic variations.
The conference of 1929 agreed that the pursuit of "ideal" measure-
ments must be resumed within the framework of the absolute system, and
from the 1930's on this became the direction of fundamental electrical re-
search. The same decade saw a marked acceleration in the work of extend-
ing the range of measurement of electrical quantities. Here, earlier pioneer
work such as Dr. Herbert B. Brooks' development of the deflection potentiom-
eter for measuring current and voltage in lamp testing came to full fruition.
It was the first of many highly specialized potentiometers he subsequently
designed.11
These lines of research continue to the present day at the Bureau and
in the electrical standards laboratories abroad. Bureau research alone in
the field of modern electrical measurement has been reported in almost 300
separate publications. The early work of Rosa, Wolff, Grover, Agnew, Wen.
ner, Vinal, and Lloyd was continued in the l920's and 1930's by Curtis,
Brooks, and Silsbee, by Sanford, Snow, Thomas, and Moon, and from 1940
on by Curtis, Snow and others.12
In the early years of electrical research at the Bureau, something more
than international agreement on standards of measurement, and provision of
quantitative standards and instruments for the industry, was at stake. Out
of its research, the Bureau also recommended to the industry equally im-
portant, if not equally welcome, standards of a quite different nature, those
of service and safety.
S33 (Brooks, 1906).
"Lyman J. Briggs, "Early work of the NBS," Sci. Mo. 73, 167 (1951); F. Silsbee,
"Establishment and maintenance of the electrical units," NBS C475 (1949); F. B. Silsbee,
"Extension and dissemination of the electrical and magnetic units by the NBS," NBS
C531 (1952).