Abstract
THE annual report of the Director of the Bureau of Standards (Government Printing Office, Washington, 1932) shows the trend of scientific developments during last year. The increase in the industrial applications of very low temperatures has made it advisable to extend the scale downwards from—100° C. to—259° C. and a temporary scale covering this range has been established. Fire tests have been made on the new welded steel floors which are now being used in buildings. They consist of steel floor plates welded to beams spaced two feet apart. Tests were made with fire both above and below the floor. Gas appliances found quite satisfactory at sea level develop defects when used in cities at high altitudes. The causes of these defects are being investigated. Perhaps the most spectacular advance made during the year has been to increase the accuracy of the primary frequency standard to one part in ten million. Regular transmissions of standard high-frequency waves at a frequency of 5,000 kilocycles per second are broadcast every Tuesday for four hours. The accuracy obtained is one cycle per second, that is, one part in five million. The ionised layer in the atmosphere has been determined to be the major controlling factor in the long distance transmission of radio waves. The measurement of the height of this layer is of primary importance in interpreting transmission conditions and increasing our knowledge of radio wave transmission. Using improved equipment, these measurements were made on one day in each week throughout the year. An automatic recorder is now in use which makes continuous measurements. Useful work is done in making careful analyses of samples of ores, alloys, pure metals, cement and pure chemicals. These samples are sold to industrial laboratories and are used for checking their own methods and results. This plan has contributed greatly to the precision of the analytical work in these laboratories and the project is self-supporting.
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U.S. Bureau of Standards. Nature 131, 394 (1933). https://doi.org/10.1038/131394a0
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DOI: https://doi.org/10.1038/131394a0