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

TECHNOLOGICAL VS. BASIC RESEARCH 465
And science and industry also needed the made by the Bureau
of the dielectric constants of liquids, both inorganic and organic.99
Equally extensive work was done in standard samples, the array of
materials maintained by the Bureau and certified as to their chemical com-
position or certain physical or chemical properties. Begun in 1905 with
the preparation of four types of cast iron, by 1911 the Bureau stock com-
prised 37 samples of steels, brasses, ores, limestone, and sugars, and 100
standard combustion samples used to standardize In 1951
the Bureau listed more than 500 distinct materials, of which 225 were certified
for chemical composition and some 90 of these prepared specifically for
spectrographic analysis. Others certified such properties as acidity, viscosity,
melting point, density, index of refraction, and heat of combustion. Over
25,000 samples were prepared and distributed that year, for the use of Federal
agencies and industry in checking tests, controlling manufacturing operations,
and settling disputes between producers and consumers.101
Among the newest samples were a tin-bearing steel, a tungsten steel,
and two nickel-chromium.molybdenum steels. An additional 32 standard
samples of hydrocarbons brought the total of these compounds to 92, and 15
new standards for color or tint made 28 color standards available. Other
samples included radioactive iodine and phosphorus for use in tracer microg.
raphy, radium gamma.ray standards, radioactive carbon and radon standards,
and a series of pH standards.
Work on the pH samples had begun back in 1940 at the urging of the
National Canners Association, of dairymen, dry cleaners, textile manufac.
turers and other groups. The control of acidity was also a problem in
manufacturing pharmaceuticals, paper, leather, dyes, sugar refining, and
biological materials. Lack of a universally accepted definition of the pH
scale, or hydrogen ion concentration, by which the degree of acidity was
measured, resulted in frequent confusion and disagreement.'°2 After almost
8 years of study and consultation with industry, the Bureau estab-
lished four standardized substances, representing pH 2, 3.5, 10, and
NBS Annual Report 1950, p. 50; Annual Report 1951, p. 42; R. D. Huntoon and
A. G. McNish, "Present status of research on the physical constants * * s," Nuovo
Cimento (Rome), 6, 146 (1957).
See ch. II, p. 93; NBS Annual Report 1911, P. 80.
101 Harry A. Bright, "Standard samples program of the NBS," Anal. Chem. 23, 1544
(1951); C398 "Standard samples" (1932) and Supplement (1946); NBS Annual Report
1951, p. 85; C552 "Standard samples" (1954), second ed. (1957); James I. Hoffman,
"The evolution of certified reference materials," Anal. Chem. 31, 1934 (1959).
'°' Hearings * * 1940 (Apr. 21, 1939), pp. 162, 379; Hearings * * * 1946 (Dec. 9,
1939), pp. 136—139; RP1495 "Provisional pH values for certain standard buffer solu-
tions" (R. G. Bates, W. J. Hamer, et al., 1942); LC993, "Standardization of pH meas-
urements" (1950).