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

GEORGE KIMBALL BURGESS 247
Bureau nevertheless continued limited research on physical constants all
through the 1920's and into the thirties, improving its ammonia tables, pub-
lishing steam tables for turbine engineering, petroleum tables, a series of
papers and a book on the properties and constants of water in all its phases,
and establishing new points on the international temperature scale.79
A note of considerable interest to physicists appeared just before
the first of the airplane ignition troubles arrived in the electrical division
in 1917 when Dr. Silsbee published a salient observation he had made on
electrical conduction in metals at low temperature. It was well known that
resistance to electrical current vanishes in certain metals at very low tem-
peratures, resulting in electrical superconductivity. In 1911 the Dutch
physicist, Kamerlingh Onnes, had found in separate experiments that this
phenomenon of superconductivity was destroyed if the current exceeded
a critical value, and was also destroyed if an external magnetic field of
more than a critical value was applied.
Dr. Silsbee saw that these two effects were not independent. The
result was the Silsbee hypothesis, "that the effect of electrical current on the
critical temperature of a superconductor is caused by the magnetic field
produced by the current"—a valuable clue to a more satisfactory theory
of the superconductive state and of metallic conduction in general.8°
Two publications illustrated the progress of 8 years of Bureau research
in polarimetry and saccharimetry under Frederick J. Bates. The seven.page
circular of 1906 on the simple verification of polariscopic apparatus became
a 140.page work by 1914, establishing the basic principles of modern
polarimetry.81 In that period the sugar industry acquired through the
Bureau a variety of improved instruments, better apparatus, and a wealth
of fundamental data; and Bureau investigations of the rare sugars, in criti-
cal supply during the war, were to lead to a wholly new industry in this
country—of which more later.
For almost a century before the founding of the Bureau, analysis
of chemical elements through their emission spectra had been the subject
(1) C142, "Tables of thermodynamic properties of ammonia" (1923). (2) RP691,
"Tables for the pressure of saturated water vapor in -the range 0° to (Osborn
and Meyers, 1934); NBS Annual Report 1939, p. 53. (3) RP11O5 "Supercooling and
freezing of water" (Dorsey, 1938) ; Dorsey, Properties of Ordinary Water-Substance
(New York: Reinhold, 1940). (4) C57, "U.S. standard tables for petroleum oils"
(1916); M97, "Thermal properties of petroleum products" (Cragoe, 1929). (5) RP-
1189, "International Temperature Scale and some related physical constants"
(Wensel, 1939).
'° S307 (1917); interview with Dr. Silsbee, May 21, 1963. For later studies in super-
conductivity, see NBS Annual Report 1948, p. 207, and ch. VIII, pp. 466-467.
C12 (1906) and C44 (1914; 2d ed., 1918). By 1942 the latter circular had been
superseded by C440, a tome of 810 pages.