Abstract
THE periodical comparison of the Standards of Length and Mass with the Parliamentary copies was due in 1932, and the Board of Trade has just issued a report of 56 pages on the results obtained. The work has been carried out in the Metrology Department of the National Physical Laboratory. As compared with the measurements made in 1922, the four parliamentary copies of the Standard Yard have decreased in length as compared with the Standard itself by 28 millionths of an inch, a change which must be attributed in part at least to an increase in length of the Standard Yard. The British copy of the metre has been compared with the Sevres copies of the Prototype Metre and has been found 0-66 parts in a million short, as compared with 0-60 parts in 1922. Two other copies have retained the lengths they had in 1922. Four Parliamentary copies of the Standard Pound weigh 3.6 and 1.1 thousandths of a grain more, and 0.7 and 3.0 thousandths less than the Standard respectively, the changes since 1922 being slight. The British National copy of the kilogram has been compared with the International Prototype and found to be 58 millionths of a gram too heavy, in good agreement with the 1922 value. The pound has been remeasured as 453-592338 grams. It is highly desirable that a new series of pound weights should be constructed of more stable materials than the present standards.
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Imperial Standards. Nature 137, 392 (1936). https://doi.org/10.1038/137392c0
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DOI: https://doi.org/10.1038/137392c0