Standard of Mass, Avoirdupois Pound
This gold-plated brass standard of mass in cylindrical form has a circumferential groove instead of a knob to facilitate its handling. In 1834 the Imperial Troy Pound of 1758 was destroyed by fire. Using two platinum troy pounds which had been carefully compared with the lost standard, Professor Miller of the British Standards Commission constructed a new platinum troy pound and from that a new platinum imperial avoirdupois pound. As a part of this work, gilded bronze copies were distributed to English-speaking nations, and copy No. 5 was received in 1856 as a gift from Great Britain to the United States. It was reported that Ferdinand R. Hassler's star pound agreed with this copy within grain, or 1 part in 7 x 106, a truly remarkable achievement. Comparisons between the two platinum weights and the Kilogram of the Archives have provided the basis for the currently accepted relation: 1 avoirdupois pound = kilogram.
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