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

34 AT THE TURN OF THE CENTURY
technic Institute faculty, complained in the pages of Science magazine that
he had to contend with eight different "authoritative" values for the U.S.
gallon, including two accepted by the U.S. Pharmacopoeia, three found in
current standard chemical textbooks, one in Oldberg's Weights and Meas-
ures (1885), and two in Treasury Department reports—that given by Bache
in his 1857 report describing Hassler's 8.3389-pound gallon and a currently
adjusted standard, an 8.3312-pound gallon. In this confusion, Professor
Mason declared he had elected to work with a ninth value, one he had deter.
mined for himself.
Although dignified by the term "standard," said Professor Mason, the
truth was, "the U.S. gallon has no statutory existence whatever," nor had
any of our common weights and measures with the single exception of the
troy pound. "It seems * * * highly desirable that this whole question
of standards and relation of weight to measure, be finally settled by law, and
preliminary to this, by a new scientific investigation."
Thomas C. Mendenhall, author of A Century of Electricity (1887)
and in charge of weights and measures as superintendent of the Coast Sur-
vey from 1889 to 1894, fully agreed: "The system of weights and measures
in customary use is so confusing, so unscientific, and, in some instances,
apparently so contradictory that it is difficult to write of it, even briefly,
without falling into error." 48 Permissive use of standards, poor construc-
tion of commercial weights and measures, and the progress of science had
long since combined to vitiate the merits of Hassler's good work.
Some degree of the confusion in precision measurement at least may
be traced to Hassler's standard of length—and the basis for all the other
standards. As Mendenhall said: "The Troughton 82-inch scale was for-
merly accepted as a standard of length, but for many years it has not been
actually so regarded. By reason of its faulty construction it is entirely
unsuitable for a standard, and for a long time it has been of historic interest
only."
The hazard in Hassler's yard measure, based on the Troughton scale,
seems to have been first pointed out by John Henry Alexander, Maryland
metrologist and later professor of natural philosophy at the University of
Maryland. For lack of the necessary equipment, Alexander carried out
many of the metrological tests for the construction of his yard measures for
P. Mason, "Confusion in weights and measures," Science, 20, 358 (1892).
48 Mendenhall, Science, 21, 79—80 (1893).
Upon completion of construction of its new imperial standards in 1855, Great Britain
presented copies of the yard and avoirdupois pound to the United States. The new
bronze yard No. 11, when compared with the Troughton yard, revealed that the accepted
36 inches of the Troughton scale was 0.00087 inch longer than the British imperial yard.
Since the new yard was far superior as a standard of length, the Office of Standard
Weights and Measure adopted it as the U.S. standard. NBS M64 (1925), pp. 12—14.