Thomas Jefferson Papers

From Thomas Jefferson to John Rutherford, 25 December 1792

To John Rutherford

Philadelphia Dec. 25. 1792.


I have considered, with all the attention which the shortness of the time would permit, the two motions, which you were pleased to put into my hands yesterday afternoon, on the subjects of weights and measures, now under reference to a committee of the Senate, and I will take the liberty of making a few observations thereon.

The first I presume is intended as a basis for the adoption of that alternative of the Report on measures and weights which proposed retaining the present system, and fixing it’s several parts by a reference to a rod vibrating seconds, under the circumstances therein explained. And to fulfil it’s object, I think the resolutions there proposed should be followed by this ‘that the standard, by which the said measures of length, surface and capacity shall be fixed, shall be an uniform cylindrical rod of iron, of such length as, in latitude 45.° in the level of the ocean, and in a cellar or other place of uniform natural temperature, shall perform it’s vibrations, in small and equal arcs, in one second of mean time: and that rain-water be the substance to some definite mass of which the said weights shall be referred.’ Without this the committee employed to prepare a bill on these resolutions, would be uninstructed as to the principle by which the senate mean to fix their measures of length, and the substance by which they will fix their weights.

The second motion is a middle proposition between the first and the last alternatives in the Report. It agrees with the first in retaining some of the present measures and weights, and with the last, in compounding and dividing them decimally. If this should be thought best, I take the liberty of proposing the following alterations of these resolutions.1

2d. For ‘metal’ substitute ‘iron.’ The object is to have one determinate standard. But the different metals having different degrees of expansibility there would be as many different standards as there are metals, were that generic term to be used. A specific one seems preferable, and ‘iron’ the best because the least variable by expansion.

3d. I should think it better to omit the chain of 66. feet, because it introduces a series which is not decimal, viz. 1: 66: 80. and because it is absolutely useless. As a measure of length it is unknown to the mass of our citizens; and if retained for the purpose of superficial measure, the foot will supply it’s place and fix the acre as in the 4th. resolution.

4th. For the same reason I propose to omit the words ‘or shall be 10. chains in length and 1. in breadth.’

5th. This resolution would stand better if it omitted the words ‘shall be one foot square and one foot and twenty cents of a foot deep, and.’ because the second description is perfect and too plain to need explanation. Or if the first expression be preferred, the second may be omitted as perfectly tautologous.

6th. I propose to leave out the words ‘shall be equal to the pound Avoirdupois now in use, and’ for the reasons suggested on the 2d. resolution, to wit, that our object is to have one determinate standard. The pound Avoirdupois now in use is an indefinite thing. The committee of parliament reported variations among the standard weights of the exchequer. Different persons weighing the cubic foot of water, have made it, some more, and some less than 1000 ounces avoirdupois, according as their weights had been tested by the lighter or heavier standard weights of the exchequer. If the pound now in use be declared a standard, as well as the weight of 16,000 cubic cents of a foot of water, it may hereafter perhaps be insisted that these two definitions are different, and that being of equal authority, either may be used, and so the standard pound be rendered as uncertain as at present.

7th. For the same reason I propose to omit the words ‘equal to seven grains Troy.’ The true ratio between the Avoirdupois and Troy weights is a very contested one. The equation of 7000. grains Troy to the pound Avoirdupois is only one of several opinions, and is indebted perhaps to it’s integral form for it’s prevalence. The introduction either of the Troy or Avoirdupois weight into the definition of our Unit, will throw that Unit under the uncertainties now inveloping the Troy and Avoirdupois weights.

When the House of representatives were pleased to refer to me the subject of weights and measures, I was uninformed as to the hypothesis on which I was to take it up. To wit whether on that that our citizens would not approve of any material change in the present system, or on the other, that they were ripe for a complete reformation. I therefore proposed plans for each alternative. In contemplating these I had occasion to examine well all the middle ground between the two, and among others which presented themselves to my mind was the plan of establishing one of the known weights and measures as the unit in each class, to wit, in the measures of lines, or surfaces, and of solids, and in weights, and to compound and divide them decimally. In the class of weights I had thought of the ounce as the best unit, because calling it the thousandth part of a cubic foot of water, it fell into the decimal series, formed a happy link of connection with the system of Measures on the one side, and of Coins on the other by admitting an equality with the dollar without changing the value of that, or it’s alloy materially. But on the whole I abandoned this middle proposition on the supposition that if our fellow-citizens were ripe for advancing so great a length towards reformation as to retain only four known points of the very numerous series to which they were habituated, to wit, the foot, the acre, the bushel and the ounce, abandoning all the multiples and subdivisions of them, or recurring for their value to the tables which would be formed, they would probably be ripe for taking the whole step, giving up these four points also, and making the reformation complete; and the rather as in the present series2 and the one to be proposed there would be so many points of very near approximation, as, aided in the same manner by tables, would not increase their difficulties, perhaps indeed would lessen them by the greater simplicity of the links by which the several members of the system are connected together.—Perhaps however I was wrong in this supposition. The representatives of the people in Congress are alone competent to judge of the general dispositions of the people, and to what precise point of reformation they are ready to go. On this therefore I do not presume to give an opinion, nor to pronounce between the comparative expediency of the three propositions, but shall be ready to give what aid I can to any one of them which shall be adopted by the legislature. I have the honor to be with perfect respect, Sir Your most obedient & most humble servt

Th: Jefferson

RC (George Green Shackelford, on deposit ViU); at foot of first page: “Mr. Rutherford”; endorsed: “No 3 Letter from Mr. Jefferson on the motion relative to measures and weights.” PrC (DLC). FC (Lb in DNA: RG 360, DL). Tr (DLC: James Monroe Papers); docketed by Monroe.

TJ’s letter to John Rutherford, a Federalist senator from New Jersey, represented his last major effort as Secretary of State to secure legislative approval of the reforms he had advocated in his celebrated Report on Weights and Measures. In that document, which he submitted to Congress in July 1790 and which reflected the rationalistic spirit of the Enlightenment, TJ proposed two alternatives for consideration: a relatively limited standardization of the existing system of American weights and measures; and the complete decimalization of that system. TJ made clear in his report, however, that he preferred the latter alternative (see Document vii in the group of documents on the Report at 4 July 1790).

TJ’s proposals failed to engender significant support in Congress. After considering his report the Senate resolved in March 1791 that it would be inexpedient to alter the American system of weights and measures until Parliament and the National Assembly had acted on plans then before them for reforming the British and French systems. In response to a plea by Washington in October of that year for the establishment of a uniform system of weights and measures, however, the Senate reconsidered the matter and appointed a committee to take up this issue. The committee submitted a report in April 1792 that reflected TJ’s call for decimalization, but the Senate deferred consideration of it until the next session of Congress and had the committee’s report printed in the interim (JS description begins Journal of the Senate of the United States, Washington, D.C., 1820–21, 5 vols. description ends , i, 225, 226, 292, 327, 335, 420–1; National State Papers description begins Eileen D. Carzo, ed., National State Papers of the United States, 1789–1817. Part II: Texts of Documents. Administration of George Washington, 1789–1797, Wilmington, Del., 1985, 35 vols. description ends , xiii, 26–7).

When Congress reconvened in November 1792 it soon became apparent that the Senate was divided over TJ’s proposals. The Senate took the April 1792 committee report under consideration on 6 Dec. and considered a motion to recommit the report and request the committee that had prepared it to draft a bill “for rendering the weights and measures of the United States uniform and invariable, retaining in general the weights and measures now in use” (JS description begins Journal of the Senate of the United States, Washington, D.C., 1820–21, 5 vols. description ends , i, 461). Further consideration of this motion and the committee’s report was postponed until 17 Dec. when the first of the two motions mentioned by TJ was offered by an unidentified member. The new motion, which was obviously made by an advocate of standardization, proposed that consideration of the April 1792 report be postponed and that “the present measures of length be retained and fixed by an invariable standard; that the measures of surface remain as they are, and be invariable also as the measures of length to which they are to refer; that the unit of capacity, now so equivocal, be settled at a medium and convenient term, and defined by the same invariable measures of length, that the more known terms in the two kinds of weights be retained, and reduced to one series, and that they be referred to a definite mass of some substance, the specific gravity of which never changes; and that a committee be appointed to bring in a bill accordingly” (same, 463). On 18 Dec. the Senate deleted the final clause of this motion and then debated the second motion referred to by TJ, which sought to achieve a middle ground between standardization and decimalization. This motion, the author of which has not been identified, reads as follows:

“1st. That the units of the measures and weights of the United States shall be equal to certain measures and weights now in use.

“2d. That the standard for the measures and weights of the United States be an uniform cylindrical rod of metal, of such length as in the latitude of forty-five degrees, in the level of the ocean, and in a cellar of uniform natural temperature, shall perform its vibrations in small and equal arcs in one second of mean time, and which standard rod shall be divided into four hundred and eighty-nine equal parts.

“3d. That the unit of measures of length shall be a foot, which shall be equal in length to one hundred parts of the aforesaid standard rod.

“That sixty-six feet shall be a chain, and eighty chains a mile.

“4th. That measures of surface be made by squares of the measures of length; but in the case of land the unit shall be an acre, which shall contain forty three thousand five hundred and sixty square feet, or shall be ten chains in length and one in breadth.

“5th. That the unit of the measures of capacity shall be a bushel, which shall be one foot square, and one foot and twentyfive cents of a foot deep, and shall contain one cubic foot and a quarter.

“6th That the unit of weights shall be a pound, which shall be equal to the pound Avoirdupois, now in use, and shall be equal in weight to a quantity of rain water, twenty cents of a foot square, and forty cents deep, or sixteen thousand cubic cents of a foot, measured and weighed in a cellar of uniform natural temperature.

“7th That the units of the measures and weights of the United States shall be divided into cents or hundredth parts, and where necessary into milles or thousandth parts, and in the case of weights the mille shall be divided into seven grains, equal to seven grains Troy.”

After an inconclusive debate the Senate referred this motion and the amended motion of the 17th to a new committee chaired by Rutherford, who submitted them to TJ for comment (same, 464).

TJ’s recommendations strongly influenced the report that Rutherford’s committee submitted to the Senate on 29 Jan. 1793. Advocating a mixture of standardization and decimalization, this report consisted of six resolutions and an accompanying explanatory statement. These resolutions corresponded to the second through the seventh sections of the motion offered to the Senate on 18 Dec. 1792, and, except for the retention of the section about the chain of 66. feet, they incorporated all of the alterations suggested by TJ in the letter above. Despite these changes, however, the Senate merely ordered that the committee’s report be printed and then decided to postpone consideration of it until the next session of Congress, thereby frustrating TJ’s final effort to obtain legislative approval for a uniform system of weights and measures in the United States (same, 476, 482; National State Papers description begins Eileen D. Carzo, ed., National State Papers of the United States, 1789–1817. Part II: Texts of Documents. Administration of George Washington, 1789–1797, Wilmington, Del., 1985, 35 vols. description ends , xv, 232–4). See also C. D. Hellman, “Jefferson’s Efforts towards the Decimalization of United States Weights and Measures,” Isis, xvi (1931), 288–307.

For a brief sketch of Rutherford, a gentleman farmer and lawyer who attended the College of New Jersey and represented New Jersey in the Senate from 1791 until his resignation in 1798, see Richard A. Harrison, ed., Princetonians 1776–1783: A Biographical Dictionary (Princeton, 1981), 107–12.

1TJ first wrote “the resolutions proposed” before altering the passage to read as above.

2Word interlined in place of “system.”

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