The National Institute of Standards and Technology (NIST) is the official custodian of the Kilogram Prototype, a 128-year-old glistening platinum iridium cylinder that serves as the theoretical starting point for all derivative weight calibrations in the United States.
The idea of measurement standards goes back to ancient days and is an essential foundation for trade and commerce; you can’t exchange treasure for food without first agreeing how much of each is on the table. But it wasn’t until the Age of Enlightenment that serious efforts were made to agree on international standards to replace the inconsistent hodgepodge of regional pounds, feet, and miles.
In 1875 an international conference ratified the Treaty of the Metre and recognized France’s Le Grande K as the mother standard against which all other standard kilograms would be set. This represented a major scientific breakthrough for the world community but still involved a degree of grease and sweat manual labor.
NIST mechanical engineer Dr. Jon Pratt tells us that “they…
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