Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States

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The "Plan for Establishing Uniformity in the Coinage, Weights, and Measures of the United States" was a report submitted to the U.S. House of Representatives on July 13, 1790, by Secretary of State Thomas Jefferson.

At the First United States Congress, which met in 1789 when the decimal metric system had not yet been developed in France, the system of units to be used in the future USA was one point of discussion. Under the Constitution (article I, section 8), the Congress has the constitutional right to decide on a standard of weights and measures. On January 2, 1790, George Washington urged Congress to address the need for the uniform system of weights and measures, and on January 15, 1790, the House of Representatives requested Thomas Jefferson to draw up a plan.[1]

The decimal dollar had already been agreed upon in principle in 1785,[2] but would not be implemented until after passage of the Mint Act in 1792. In mid-1790 Jefferson proposed two systems of units. The first was evolutionary, and was based on refinement of the definitions of the units of the existing English system, as well as simplification of their relationship to each other. The second system was revolutionary, and was based on units linked by powers of ten, very similar to the decimal metric system which would be proposed in France. The base units for length, mass, and volume in Jefferson's revolutionary system (named the foot, the ounce, and the bushel, respectively) were relatively close in size to their pre-existing counterparts and bore identical names, although the manner in which they were defined was very different.

Jefferson's proposal was the world's first scientifically based, fully integrated, decimal system of weights and measures.[1]

The seconds pendulum basis[edit]

In coordination with scientists in France, Jefferson selected the seconds pendulum at 45° latitude as the basic reference. For technical reasons, he proposed using a uniform rod as the pendulum rather than a traditional pendulum. The pendulum was estimated to be 39.14912 English inches long (in the inches of that time—it wasn't until much later that the inch was defined to be 25.4 mm), or 1.5 times that for a vibrating rod (58.72368 inches).

More traditional proposal[edit]

In the evolutionary approach, the foot was to be derived from one of these lengths by a simple integer factor, which would be either three (pendulum) or five (rod), i.e. lengthening it from the traditional value by 1.04970¯6 inches to ca. 331.463 mm or shortening it by 0.255264 inches to ca. 298.317 mm. For practical purposes he wanted the rod to be 58¾ (new) inches long, an increase of less than 0.045%.

Jeffersonian conservative proposal
line 587 15 in standard rod
inch = 10 lines
foot = 12 inches
yard = 3 feet
ell = 3¾ feet
fathom = 6 feet
perch, pole = 5½ yards
furlong = 40 poles
mile = 8 furlongs
league = 3 miles
rood = 40 square poles
acre = 4 roods
gill = ¼ pint
pint = ½ quart
quart = ½ pottle
pottle = ½ gallon
gallon = 270 cubic inches
peck = 2 gallons
bushel, firkin = 4 pecks
strike, kilderkin = 2 bushels or firkins
coomb, barrel = 2 strikes or kilderkins
quarter, hogshead = 2 coombs or barrels
tierce = 4/3 hogshead
pipe, butt, puncheon = 2 hogsheads
ton = 2 pipes
grain = 1/24 pennyweight
pennyweight = 1/18 ounce
ounce = 1/1000 weight of 1 cubic foot of rain water at standard temperature
pound = 16 ounces

Decimal system based on the foot[edit]

Jefferson's proposed decimal system preceded the adoption in France of the decimal metric system, although both developed simultaneously. In France, the metre was to be defined as the ten-millionth part of an arc between the North Pole and the equator. Jefferson's system was based on the length of a rod oscillating seconds at 45 degrees latitude, with the foot defined as one fifth of the length of such a rod. Similar to the French system, Jefferson proposed a system of units linked directly by powers of ten. However, Jefferson's system did not make use of the concept of prefixes, which were of great importance in the French system. Instead, the names of old units were carried over into the new system for decimal multiples of the base units, giving them new values.

Asserting the value of such thorough reform to the existing system of weights and measures, the report stated:

But if it be thought that, either now, or at any future time, the citizens of the United States may be induced to undertake a thorough reformation of their whole system of measures, weights and coins, reducing every branch to the same decimal ratio already established in their coins, and thus bringing the calculation of the principal affairs of life within the arithmetic of every man who can multiply and divide plain numbers, greater changes will be necessary.

The following table lists the units of the Jeffersonian decimal system, and their relationship with one another. The values of these units are based on Jefferson's proposal of a foot that was equal in length to one-fifth of a second rod, one quarter-inch shorter than the foot in use at the time, and approximately equal to 0.298461684 m.[3]

Jeffersonian decimal proposal
Value relative to base unit SI equivalent
Point 0.001 0.29846 mm
Line 0.01 2.9846 mm
Inch 0.1 2.9846 cm
Foot 1 0.29846 m
Decad 10 2.9846 m
Rood 100 29.846 m
Furlong 1000 298.46 m
Mile 10000 2.9846 km
Rood 1 (one square rood) 890.78 m2
Double Acre 10 8907.8 m2
Metre 0.001 (one cubic inch) 26.857 mL
Demi-pint 0.01 268.57 mL
Pottle 0.1 2.6587 L
Bushel 1 (one cubic foot) 26.587 L
Quarter 10 265.87 L
Last / Double Ton 100 2658.7 L
Mite 0.0001 2.6587 mg
Minim, Demi-grain 0.001 26.587 mg
Carat 0.01 265.87 mg
Double Scruple 0.1 2.6587 g
Ounce 1 (mass of one cubic inch of pure water) 26.587 g
Pound 10 265.87 g
Stone 100 2.6587 kg
Kental 1000 26.587 kg
Hogshead 10000 265.87 kg

The transcript of the original document gives the value of a kental as 16 stones at one point and 10 stones in another point. 10 was presumably the intended value, given the otherwise consistent decimalization.

Subsequent developments[edit]

Under the United States Constitution, Article 1 Section 8, Congress shall have power "To coin Money, regulate the Value thereof, and of foreign Coin, and fix the Standard of Weights and Measures". In his first annual message to Congress (what later came to be called "State of the Union Addresses") on January 8, 1790 (a few months before Jefferson's report to the House of Representatives), George Washington stated, "Uniformity in the currency, weights, and measures of the United States is an object of great importance, and will, I am persuaded, be duly attended to."[4]

Washington repeated similar calls for action in his second[5] and third[6] annual messages (after Jefferson's report). Jefferson's decimal proposal had the support of Alexander Hamilton, James Madison, James Monroe, and George Washington. Robert Morris was a powerful opponent of the proposal.[1] In late 1791 the Senate appointed a committee to report on the subject and make recommendations. The committee reported in April 1792, unanimously endorsing Jefferson's decimal system. The Senate was slow to act on the matter and while they delayed events in France complicated the issue. Although French scientists working on a decimal system had originally supported using the seconds pendulum as a scientific basis, and Jefferson had deliberately matched his seconds pendulum proposal to the French one, based on a measurement at the latitude of Paris, the French decided to use the length of a meridian of the Earth instead of a seconds pendulum. This and other developments changed what had promised to be an internationally developed system into a strictly French project. Jefferson wrote, "The element of measure adopted by the National Assembly excludes, ipso facto, every nation on earth from a communion of measurement with them."[1]

The Senate continued to consider Jefferson's two proposals, along with a number of new proposals, for several years. In 1795 a bill titled "An Act directing certain experiments to be made to ascertain uniform standards of weights and measures for the United States" was passed by the House and was approved by committee in the Senate, but on the last day of the session the Senate said it would consider the bill during the next session. The bill was never taken up again. In 1795 the Northwest Indian War, which for years had prevented the surveying and sale of land in the Northwest Territory came to an end. A land rush of settlers, surveyors, squatters, and others rapidly pushed into the region and the federal government had a sudden and intense need to establish a method for surveying and selling land. 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.[1]

See also[edit]


  1. ^ a b c d e Linklater, Andro (2003). Measuring America: How the United States Was Shaped by the Greatest Land Sale in History. Plume. pp. 103–142. ISBN 978-0-452-28459-3. Retrieved 14 May 2012.
  2. ^ Journals of the Continental Congress, Wednesday, July 6, 1785
  3. ^ Hellman, C. Doris (Nov 1931). "Jefferson's Efforts towards the Decimalization of United States Weights and Measures". Isis. 16: 266–314.
  4. ^ The American Presidency Project, George Washington: First Annual Message, accessed October 13, 2006
  5. ^ The American Presidency Project, George Washington: Second Annual Message, accessed October 13, 2006
  6. ^ The American Presidency Project, George Washington: Third Annual Message, accessed October 13, 2006


  • The Writings of Thomas Jefferson, Monticello Edition, Washington, D.C.: The Thomas Jefferson Memorial Association, 1904, Vol. 3 pp. 26–59.

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