History of Force Measurement in the US – Part 15

While our last installment left off with the human eye, in terms of color perception, this one begins with teeth, as it relates to the Bureau’s investigation of dental amalgams. In 1917, the Surgeon General of the Army approach the Bureau with this problem because of the widespread issue he faced of dealing with dental issues. Insiders from the dental industry worked with the Bureau, which eventually concluded that half or more of dental materials were unsatisfactory. Although dentists, manufacturers or dental materials and dental testing labs cooperated with the Bureau, the government, in the form of the Commerce Department, suppressed the unsatisfactory findings for fear of creating a loss of public confidence. The Bureau helped identify the best adhesives, filling materials and more for use in the dental industry and within about 10 years, unacceptable materials had dropped from 50% to 10%.


Bureau efforts during the 1920s continued to span a variety of industries but the construction industry was probably the source of the most investigations. From elevator safety to fire resistance, almost 100 projects relating to construction were taking place in all divisions at the

Bureau – electrical, heat, chemistry, metallurgy and more.


In an earlier installment, we showed how the Bureau became involved in the manufacture of optical glass for binoculars, scientific instrumentation and the like. Private industry showed little interest in taking over this manufacturing process, so the Bureau continued its manufacture of glass, mostly for the military. In 1924, the Bureau attempted to cast a 69.5 inch disk for a telescope. At the time, only the country only had two other large glass plants, both with equipment from Europe, whose technology was a trade secret. The Bureau had to draw on their knowledge and experiment. The first four attempts all cracked during cooling, but the fifth attempt, poured in 1927. After some seven months of controlled cooling, the disk, which weighed 3,800 pounds, was declared to be a success.


In addition to the large disk, the optical glass section’s other great triumph was the creation of the Bureau’s first standard of planeness created in 1926. It was used as a standard of straightness and planeness whose accuracy measured to five-millionths of an inch. It was also used to produce standard angles and to calibrate instruments for measuring curvature. The glass industry of the time also saw major development through the manufactures of automobile windshields and windows.


The automobile industry continued to expand by leaps and bounds, despite warnings about the scarcity of petroleum resources, which were estimated to be exhausted in 10 years. The need thus arose to ensure the quality of gasoline on the market, which, through practices meant to conserve it, would often lead to a substandard product for the consumer. The Bureau recognized that quality gasoline would make a car’s engine perform more efficiently, thus reducing consumption.


A whole new area of investigation was born at the Bureau, which published papers on efficiency characteristics of different fuels and oils for use in cars. The Bureau tested various types of antifreeze, but didn’t endorse any as none worked better than alcohol and water. Studies were also conducted on fuel-air rations and engine temperatures, among other things. An investigation concerning brakes for the Army Motor Transportation Corp eventually lead to research on stopping distances and reaction times of drivers. This data collected by the Bureau was used in driver manuals for years after. Some other Bureau studies that grew out of the auto industry were investigations regarding rubber (for tires) and storage batteries used in electric vehicles.


While the auto industry eventually assumed responsibility for much of its own research and development, the aviation industry was slower to become self-sufficient. Several government committees and departments were involved in regulation of the aviation industry, and all used the Bureau to conduct research on areas like engines, fuel economy, ignition, instrumentation and aerodynamics. The industry, or at least the military, was not ready in the 1920s, however, to take a chance on new technologies explored by the Bureau including helicopters and jet propulsion. The military push at the time was for “lighter-than-air” craft such as dirigibles. The Bureau supported the military by providing instrumentation for these craft, like navigation equipment, and conducting durability tests on the construction materials used. When dirigibles proved not to be a viable option for safe air travel, the focus did switch to planes, and with the promise of civilian commercial flight, the Bureau increased work on the radios necessary for ground-to-air communication and the beacons that would guide planes in flight.


**The information presented here is drawn from “Measures For Progress: A History of The National Bureau of Standards” (Rexmond C. Cochrane)


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