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

ACQUIRING NATIONAL STANDARDS 79
in the new physical laboratory, Nutting was in the midst of an investigation
of electrical discharges in gases in connection with spectrum analysis, and
Bates was at work on new methods and apparatus looking toward improved
polariscopic standards. At the request of the Treasury, Noyes and Bates
had already begun supervision of the polariscopic analysis of sugar at the
customhouses.
The engineering instruments section was currently occupied with
planning tests of gas meters, water meters, pressure gages, and other instru-
ments used in large numbers by public utilities for production control and
for determining consumer rates. By far the largest piece of equipment
destined for this section was a 100,000-pound machine for testing the strength
of building materials. It seems possible this was acquired not long after
the Bureau learned that the Reichsanstalt had under construction a new
laboratory structure, the Material Prufungs Amt, for testing engineering and
building materials.51 The Bureau similarly planned studies in the behavior
of structural and building materials when this crushing machine and other
equipment on order were properly set up in North building.
In the resistance and electromotive force section of the electrical
division, Dr. Wolff and his assistants had been kept busy making tests for
Government agencies and for the electrical industry, verifying resistance
standards for current measurements, testing standard cells, and determining
the temperature coefficients and thermoelectric properties of resistance ma-
terials. Every calibration of an electrical instrument, all ratings of electric
light bulbs, and practically every meter by which electricity was sold to
home or factory started with a measurement of the device against a 1-ohm
standard of resistance and a standard cell, by which the electrical pressure
(electromotive force), and the current were determined. The Bureau had
a number of 1-ohm manganin standards acquired at the Reichsanstalt and
reverified there from time to time, using the primary mercury standards
maintained in that laboratory. Wolff intended soon to construct a number
of his own primary mercury standards in the Bureau shops.
No such effort at independence was necessary in the case of the Clark
standard cell, the legal standard of electromotive force. At the electrical
congress held during the Columbian Exposition in 1893, its value had been
established as 1.434 international volts at 15 °C. Since then the Reichsan-
stalt, using the same cell as its standard, had determined a new value, 1.4328,
nearly 0.1 percent smaller, and the Bureau hoped to settle this discrepancy at
the next international electrical congress.
Work had just begun in the magnetism and absolute measurement of
current section, where Guthe and Rosa were in the midst of two important
Si See Hearings * * * 1906 (December 2, 1904), p. 233.