Thomas Jefferson Papers
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IV. First State of the Report on Weights and Measures, [April 1790]

IV. First State of the Report on Weights and Measures

[April 1790]

Sir Isaac Newton has determined the length of a pendulum vibrating Seconds in latitude to be 39.2 inches = 3.2666 &c feet measuring from it’s point of suspension to it’s center of oscillation.

A rod vibrating seconds must be of the same length between the point of suspension and center of oscillation: and this center will always be found at two thirds of the whole length. Such a rod then will be 58.8 Inches or 4.9 feet English measure long. The divisions and multiples of this last measure accomodating themselves not at all to the measures and weights in use with us; but the double of it, to wit, 9.8 feet doing this remarkeably well and admitting a good check being equal to the Treble of the Pendulum of equal vibration1

Let the standard of measure be the Double length of a rod or Treble length of a Pendulum vibrating seconds. It will yeild us the following series of divisions and multiples.

measures of length, or long measures
Equivalents in
English Measures
English measures
of the same name
A Line to be noted thus .01 =    .11732I.
10. lines = an Inch .1  =   1.173    1.I About ⅙ less
10. inches = a Foot 1.   =  11.738   12. 1/50 more
10. feet = the Double3 of a 1” Rod 10.   =   9.78 feet   16.5 ⅓ more
10. rods4 = a Chain5 100.   =  97.821   66. ⅓ less
10. chains = a Furlong 1000.   = 978.212  660. ⅓ less
10. furlongs = a Mile 10000.   = 9782.125
   97.821 f.sq.
5280. ⅓ less
a square Chain of Land     100 f.sq. = 9558.94 sq.f.  104.355 f.sq. } Eng.rood
 or 10890 sq.f.
4. sq. chains = an Acre     200 f.sq. = 195.642 f.sq.
 38275.8 sq.f.
 208.71 f.sq.
or 43560 sq.f.
⅛ more
Measures of capacity or solid measures.
Equivalents in
English measures
English measures of
the same name
A Cubic Inch6 .001 =   1.61749 I.   1. about ⅓ less
10. cubic inches7 = Demi-pint   .01 =  16.749  16.875 1/24 less
10. demi-pints = Pottle   .1 = 161.749 135. ⅙ more
10. pottles = a cub. foot = Bushel or Firkin   1. = 1617.496547987 c.I. ¼ less
 .936051243048 c.f.   2160.
10. bushels or firkins = a Quarter  10. =   9.3605 cub.f. 11.736 cub. feet ⅕ less
10. quarters = a Double Tun8 100. =  93.605   80. 1/7 more


Let Rain water, as the most homogeneous substance, be referred to as the standard for weights, and a cubic of that be called an Ounce.

Equivalents in English weights English Weights of same name
Avoirdupoise Troy About
= A Demigrain     .0001 .409522418 grs.   .5 gr. Troy ⅕ less
10. demigrains = a Carat     .001 4.09522418  4. equal
10. Carats = a Double Scruple     .01 40.9522418 40. 1/40 more
10. double scruples = an Ounce (cub. I. rain water)     .1  .9360512 oz.= { 409.52218
.8531717 oz.
} Troy   437.5 1/16 less
10. ounces = aPound    1. 9.360512 oz.
.585032 ℔.
.7109764. ℔. Troy  1.℔. Troy ¼ less
10. pounds = a Stone   10. 93.60512 oz.
5.85032 ℔.
7.109764 ℔. Troy  9.72 ℔. Troy ¼ less
10. stone = a Kental  100. 936.0512 oz.
58.5032 ℔.
71.09764 ℔.  100. ℔.
¼ more
10. kental= a Demi-Tun9 1000. 9360.512 oz.
585.032 ℔.
710.9764 1000. lb.
¼ more


Let the Cubic inch, or Ounce of Rain water be the standard of weight for the Unit or Dollar.

A Mill  .001 grs. Troy
10.mills = a Cent  .01 The ounce weight will be as above 409.522418
10. cents = a Dime  .1   Suppose the alloy 1/12  34.126868
10. Dimes = the Unit or Dollar 1. Remains of pure Silver in the Dollar 375.395550
10. dollars = the Eagle The Dollar as fixed by Congress had pure silver 375.64
Makes ¼ of a grain or 1/1500 of a Dollar difference   0.24445

Qu. The Quantum of alloy being arbitrary to a certain degree, might it not be so fixed as to offer an easy means of trying the purity of the coin; viz. so proportioned that it should occasion the coin to lose 1/10 of it’s weight when weighed in water?

2. Qu. Or (supposing the value of pure gold to be to that of silver as 15:1) is it more convenient so to alloy both metals as that in a golden dollar e.g. the pure metal shall be 1/15 of that in the silver dollar, and the alloy 1/15 also of that in the silver dollar: so that the alloyed masses shall be in the same proportion with the pure metals they contained?

MS (DLC: TJ Papers, 233:41955); entirely in TJ’s hand except for the date “April 1790” on verso, which is in James Madison’s hand; with deletions and interlineations, some of which are noted below. The first paragraph has lines drawn through it (see note 1); this and other alterations indicate that the MS, though at first a fair copy, became a draft for subsequent texts as to that part summarizing the proportions between the proposed decimal notation and other systems of weights and measures. A considerable number of fragments, calculations, notes, &c in Jefferson’s hand are extant and related to the above text. For convenience of reference these are numbered and described as follows:

MS 1: The quarter-leaf in TJ’s hand in DLC: TJ Papers, 233: 41971 shows that TJ took up the matter of weights and measures shortly after arriving in New York. It bears the date “1790. Mar. 28.” and reads: “The cubic foot (Eng) of water weighs 1000. oz. If the foot were divided into 10. inches, a cubic inch of water would be 1. oz. But 1 oz. is near the weight of a dollar. Cannot the Dollar, the ounce, and the inch be thus made the center of money, weights and measures e.g. declare a cube of water of the weight of a dollar shall be an inch. 10.I. a foot. [On verso:] Declare correspondence between the mile and 1’ pendulum.

geom. mile 1 = 2000 yds. or 1000 fathom
furlong 1/10 = 200  100
chain 1/100 = 20   10
fathom 1/1000 = 2    1
foot 1/10m = 7 ¼ Inches
inch 1/100M = ¾ I.
acre 10 square chains


Water the substance

1 cubic inch (Oncia) the ounce = ⅕ oz.

10 oz the ℔

10 ℔ the stone

10 stone the Kental

10 Kentals the

10 the Myriad

1/10 oz

1/100 oz

1/1000 oz

[At foot of page, ruled off from the above:] Rather take cubic foot = 12½ and call it the stone or 1/10 stone a pound = 1¼ ℔ 1/10 ℔. an ounce = 2 oz. Avoird. 1/10 oz.” This MS bears notes from 1787 to 1790: (1) “Marseilles Hotel des Princes ce 31me Mars 1787” (2) an abbreviated notation reading “amg the 1st. obj. of yr. attentn,” which may refer to the heading for a paragraph in TJ’s letter to Madison of 18 Nov. 1788; and (3) a note belonging perhaps to 1789 reading: “1200℔ for Gates’s medal-Wythe-King.” This MS is clearly the earliest record of TJ’s speculations about a system of weights and measures after he arrived in New York.

MS 2: A single sheet in TJ’s hand, DLC: TJ Papers, 233: 41966 is the first draft of the MS printed above, but contains only the comparative figures for the proposed units. The equivalent figures vary, however: the inch is 1.176 instead of 1.173 English measure; the ounce is .94119 avoirdupois and 411.770625 grains Troy instead of .9360512 and 409.52218 respectively; the cubic inch is 1.62638 English measure instead of 1.61749; and the calculation for the unit of money varies in accordance with the variation in the ounce. The figures in this MS were originally the same as those in MS printed above, but were altered by overwriting, the multiples of the units of measure and weight being altered accordingly (see note 2, below). The names of the various measures and weights are the same as in MS printed above, except that the measures of length begin with the point, and in the measures of capacity the “double Ton” is also deleted in this draft and “Last” is interlined (see note 8).

MS 3: Miscellaneous notes concerning various statutory definitions of various English weights and measures, all in TJ’s hand, undated, and written on blank address-covers of letters and other scraps of paper are to be found in DLC: TJ Papers, 233: 41953–4, 41958v, and 41959–61. These notes served as the basis for corresponding parts of the report and are sometimes repetitive. A series of equations and calculations on similar scraps of paperone of which bears a Richmond postmark of 9 April—is also to be found in DLC: TJ Papers, 233: 41956–8, 41961V-5, 41967–8, 41970, and 41980–1. Some of the notes and calculations concerning the silver content of the dollar probably belong to late 1790 and early 1791. A memo at f.41968 relates to the second query in MS printed above and also contains a calculation concerning the number of cents to be struck from copper sheets at 80 per ton—a notation probably made when TJ was preparing the report on copper coinage (see under 14 Apr. 1790). This juxtaposition of the two notes is further confirmation of the assumed date of early April 1790 for this first state of the report on weights and measures.

1All of the text to this point was struck out by TJ employing crossed and diagonal lines.

2The equivalents in all of the measures and weights are altered by overwriting (see MS 2 above).

3Above this word TJ wrote the tentative designations “Decades” and “ruthe.” This and other similar designations are in a less formal handwriting than that of the text and were obviously added after MS had served its purpose as a clear copy.

4Above this word TJ wrote the tentative designation “decades.”

5Above this word TJ wrote the tentative designations “Centuple,” “Rood,” and “Ruthe.”

6Above this word TJ wrote the tentative designation “Roquille.”

7These two words are deleted in MS and the word “Roquilles” substituted therefor.

8These two words are deleted in MS and the word “Last” substituted therefor.

9This word is deleted in MS; TJ then substituted “Pipe …” for it, after which he deleted these two terms and interlined “Hogshead.” See MS 2 above.

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