The Articles of Confederation was the immediate source that gave the central government "the sole and exclusive right and power of...fixing the Standard of Weights and Measures throughout the United States." Article IX, Section 4....During their respective tenures as Secretary of State, Thomas Jefferson and John Quincy Adams, as well as a House Committee, produced extensive studies calling for congressional adoption of uniform standards. The reports by the House and Adams rejected adopting the metric system of France and proposed no federal enforcement mechanism, leaving the application of the standards to the executives of the several states. Nonetheless, Congress did not adopt any systems of weights or measures, although the Treasury Department established standards for the pound, yard, gallon, and bushel for customs purposes.
Congress has acquiesced in (though never authorized) the use of the traditional English system of weights and measures in nonbusiness activities. In 1866, Congress authorized, but did not mandate, the use of the metric system and, since 1975, the metric system has been the "preferred system" for trade and commerce. The National Institute of Standards and Technology of the Department of Commerce periodically publishes standards for English and metric weights and measures.
“Congress did not adopt any systems of weights or measures, although the Treasury Department established standards for the pound, yard, gallon, and bushel for customs purposes. “
Our always pragmatic Founders.
The Constitution, to me, isn’t filled with grand ideals but with keen commonsense.