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

338 THE TIME OF THE GREAT DEPRESSION (1931-40)
Much of the success in securing cooperation and final agreement on these
standards was owing to the skill and diplomacy of the Bureau's chief
over those years, Dr. Eugene C. Crittenden.118
In the lull of the depression, Dr. Coblentz found time to reassess his
standards of thermal radiation, kept at the Bureau for precise calibration of
thermopiles and other radiometers used by industry, and to work on his
standards of ultraviolet radiation.119 Hospitals, as well as many industries,
had long been concerned with control of both the beneficial and harmful
effects of ultraviolet radiation, and sought means for precise calibration of
the photoelectric dosage intensity meters used for measuring radiation.
Under study since 1931, about the time ultraviolet lamps first appeared on
the market as household health aids, the Bureau standard, consisting of a
quartz.mercury arc lamp whose ultraviolet rays were calibrated in absolute
units, was ready in 1936.120
An even more critical aid to the medical profession than the standard
of ultraviolet radiation was flue Bureau's standardization of X.ray dosages.
The need arose when World War I saw new X.ray apparatus that increased
the voltage from 50,000 to 200,000 volts, and soon after the war these new
voltages began to be widely used in cancer therapy.
Even after a quarter century of experience hospital technicians and
private practitioners still operated their X.ray equipment empirically. Al.
though the early postwar apparatus, unlike previous equipment, had some
lead shielding, in cancer therapy the voltage, more or less arbitrarily estab-
lished at 140,000 volts, presented a tremendous haz'ard. Patients were rela.
tively safe since exposure times fairly well known, but cumulative
injuries to the operators working constantly with the apparatus were frequent
and often severe. The question of-these radiation hazards was first raised
at the International Congress of Radiology, held at London in 1925. Con-
Crittenden, who came to the photometry section of the Bureau from Cornell in 1909,
succeeded Rosa as chief of the electrical division in 1921, became Assistant Director of
the Bureau in 1933, Associate Director in 1945, and consultant to the Director from his
retirement in 1950 until his death 4 years later. As chairman of the personnel and
editorial committees of the Bureau for many years, he set the standards for personnel
policies and for the high quality of the scientific output of the Bureau. Serving under
all five Directors, he came to possess the most complete knowledge of the Bureau at every
level of its operation and administration.
RP578 (Coblentz and Stair, 1933).
RP858 (Coblentz and Stair, 1936); NBS Annual Report 1940, p. 71. Two projects
dear to Coblentz still unsolved at the time of his retirement were establishment of a
unit of dosage of biologically effective ultraviolet radiation and a primary standard meter
for measuring ultraviolet solar and sun radiation, for use in heliotherapy. Coblentz,
"Reminiscences of the radiometry section," Dec. 9, 1944 (NBS Historical File). With-
out Coblentz, his group turned to more pressing work in the field of X rays. Interview
with Harry J. Keegan, Feb. 12, 1964.