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

536
The small palace that is the in-
ternational Bureau of Weights
and Measures near Sèvres,
France.
APPENDIX B
After another three decades of research, which saw light wave measurements pass
from those of the elements to their isotopes, the 11th General Congress on October 14,
1960, adopted as a new definition of the meter, 1 650 763.73 wavelengths of the orange-
red radiation of the isotope of krypton with mass 86.
Adoption by the National Bureau of Standards of the new definition does 'not
invalidate the fact that the International Prototype Meter is still the major source and
support of the common measures of the United States, even though it is no longer neces-
sary to take the U.S. prototype meter to the International Bureau for comparison. And,
periodically, legislation will continue to be proposed for conversion in one degree or
another to the metric system. Its completeness, uniformity, simplicity, and widespread
use elsewhere in the civilized world make its use obligatory in almost all scientific
measurements and computations. Besides our coinage, it is found in general use in
library catalog cards, in book, pamphlet, postage, and film measurements, in describing
the properties of photographic lenses, in track and field events in athletics, in electrical
units of measurement, and in exact mechanical work. The thickness of metals, paper,
and glass is commonly measured in metric terms, as is the diameter of wire, tubing,
and similar products.
The metric system is used in microscopy and spectroscopy, in geodesy and
engineering, in the scientific measurement of mass and volume and capacity, and in
much of international commerce. No voice disputes the complexity of the system in
daily use that still necessitates, as do our "English" measures, weighing copper by one
standard, silver by another, medicine by a third, diamonds and other precious stones by
a fourth, and chemicals by a fifth, all noninterchangeable.
The varieties of units universally used in trade in the English-speaking countries
have their source in a conglomeration of discordant series with no simple relation either
between the different sets of units or between units of different size in a given series.
The uniformity in measures that the founding fathers sought has yet to be duly
attended to.