A year previous to the signing of the Treaty of the Meter in 1875, an international group of metrologists had begun investigating suitable alloys for the anticipated construction of the International Meter and Kilogram and the national prototypes. It had been determined that the standards would be constructed of an alloy of platinum-iridium, containing
10 % iridium. An alloy made in 1874 was rejected because it did not meet the required level of purity. However, several meter bars using the rejected alloy were constructed and distributed. Meter No. 12, made from the Alloy of 1874, was distributed to the United States and certified to equal 1m + 3.3µ + 8.634µ T + 0.001µ T2.
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