Queries concerning Jefferson’s Report on Weights and Measures, [ca. 20 May] 1790
Queries concerning Jefferson’s Report
on Weights and Measures
[ca. 20 May 1790]1
Quer. if a fixed temperature might not be got by referring to a thermometer—the freezing point—being the natural standard2
Quer. as to the inaccuracy of English calculations of London Pendulum.3
Quer. if mode of distributing actual standards thro’ the States sd. not be suggested at the close of the report.
Quer. would not uniform cylinders be as eas[i]ly measured & judged of, as squares.4
Quer. if the Quarter & Chauldron sd. not be measures.
pa 14/15 Quer. as to the inference from the coinciding circumstances relative to the Avod: & Troy—spec[i]fic weight of Wheat & Rain water to accurate & philosop. for antient times—& allso a cubic foot.5
pa. 3. bottom—quer. if lower extremity not a better expression—& if defined at both extremities—quer. as the measurement must be not from the upper extremity but the center of suspension.6
If the difficulty of obtaining a rod perfectly uniform in size &c not worth noting as an uncertainty, tho’ too inconsiderable to form an objection?
p. 13. wd. not the pottle be better defined by diminishing its depth—15 I. exceeds a convenient proportion to 3 I. square.7
p. 23. easy of comparison.8
Ms (DLC: Jefferson Papers). In JM’s hand. The Ms consists of two sheets. Jefferson wrote “Madison?” at the bottom of the second sheet. For the dating of the Ms, see n. 1.
1. These queries constitute the only surviving evidence of JM’s collaboration with Jefferson in preparing the famous report on weights and measures. As attested by his page citations, they were directed to the “second state” of the report, which Jefferson finished “about the 20th. of May.” Although the full extent of their collaboration cannot be known (the two must have discussed the proposed report frequently), this document by itself shows that Jefferson sought JM’s advice at the earliest stages of composing the report and that JM was fully conversant with the subject (, XVI, 607–10, 612–14, 623, 628–43, 649 n.).
2. This question apparently refers to Jefferson’s suggestion to keep the vibrating rod (the proposed standard of length) “in a cellar or other place, the temperature of which never varies” (ibid., XVI, 630).
3. See ibid., XVI, 630, 644–45 n. 6.
4. Jefferson wrote: “Cylindrical measures have the advantage of superior strength: but square ones have the greater advantage of enabling every one, who has a rule in his pocket, to verify their contents by measuring them” (ibid., XVI, 636).
5. See Jefferson’s discussion of the relationship between the “two series of weights in use among us: the one called Avoirdupois, the other Troy” (ibid., XVI, 636–39).
6. JM referred to the following passage: “This center being known to reside at one third of the whole length of the rod, measured from the bottom might be easily and accurately ascertained in practice. But the whole rod is better for a standard than any portion of it because it is sensibly defined at both it’s extremities.” A check mark, probably made by Jefferson, precedes this query. Jefferson revised the passage in his final draft (ibid., XVI, 630, 652).
7. Jefferson defined the dimensions of the pottle (two quarts) as three inches square and fifteen inches deep. On looking over this query, Jefferson made the following notation: “4½ × 5 × 6 = 135.” In the final draft he wrote: “The Pottle 3. I. square and 15. I. deep, or 4½, 5, and 6. I.” (ibid., XVI, 636, 659).
8. It is uncertain whether JM was here recommending merely a change of phraseology or suggesting that Jefferson add a table of weights and measures at the end of his report to make the existing and proposed units “easy of comparison” (ibid., XVI, 643, 649 n.). A check mark also precedes this entry.