On May 18, 1796 Congress passed "an Act for the sale of land of the United States in the territory northwest of the River Ohio, and above the mouth of the Kentucky River". This law defined a survey grid system of 6–mile–square townships divided into 1–mile–square sections, with the defining unit being the chain, specifically Gunter's chain. This was the first unit of measurement designated into law by Congress. This law and the way it defined the survey grid ended debate over Jefferson's decimal system. Origins The proposal by William Waring from 30 January 1790 was similarly decimalized as Jefferson's more radical proposal, but introduces many new names for units and its base is the equatorial seconds pendulum, i.e. determined at 0° not 45°, called pend or federal ell. A federal gallon of 0.004 cubic pends, i.e. slightly less than 4 liters and thus similar in size to the English wine gallon, is suggested as a more traditional base for liquid measures; and 9 such gallons, since almost equal to a Winchester bushel, or, more systematically, 10 gallons would form the base for dry measures. Inspired by the Avoirdupois system defining 1 cubic foot of water to weigh 1000 ounces of which there are 16 to the pound, Waring suggests a federal pound of half a cubic hand of water, which would be just short of 0.5 kg. See also Approximate conversion of units Mesures usuelles Metrication in the United States Seconds pendulum United States customary units Notes References The Writings of Thomas Jefferson, Monticello Edition, Washington, D.C.: The Thomas Jefferson Memorial Association, 1904, Vol. 3 pp. 26–59. Thomas Jefferson to House of Representatives, July 4, 1790, Report on Plan for Establishing a Uniform Currency, with Draft Copy archived at Library of Congress External links Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States, American State Papers Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States A metrication timeline that places the work of Thomas Jefferson in context How Pirates Of The Caribbean Hijacked America's Metric System by Joe Palca for NPR 1790 in the United States Systems of units Metrication in the United States History of science and technology in the United States Thomas Jefferson Works by Thomas Jefferson