Thomas Jefferson Papers

Thomas Jefferson to Amos Hamlin, 1 April 1818

To Amos Hamlin

Monticello Apr. 1. 18.

I am indebted for your letter of Jan. 12. which was exactly 2½ months in getting to my hands, & brought me the favor of your meteorological observations which bear the marks of great care and accuracy. I believe there is not a single person in this part of our country who attends to this subject, so that I am not able to offer you any thing from others. I kept pretty exact tables for a space of 7. years & then discontinued them. I state below some of the results which may perhaps be acceptable to you with the assurance of my great respect

Th: Jefferson

therm. fall of rain
Jan  36.  3.66        winds
Feb  40  3.47 N. 61 .
Mar.  46  2.92 NE. 29
Apr.  56½  3.59 E 15
May  61½  5.60 SE. 16
June  72  3.47 S. 60
July  75  6.56 S.W. 66
Aug  73  4.06 W. 47
Sep  67  5.96 N.W. 71
Oct  57  3.40 365
Nov.  45½  2.92
Dec.  37½1  1.55
 55½ 47.222

the greatest cold in the 7. years was 5½° above zero

the greatest heat was 94½°

the average temperature of the 7. years was 55½°

our coldest springwater is 54½ when the outer air is 75°

the average of a winter’s3 snow was 22½ I. covering the ground 22. days.

PoC (DLC); salutation missing, possibly due to polygraph misalignment; at head of text: “Mr Amos Hamlin”; endorsed by TJ.

For the pretty exact tables TJ kept between 1810 and 1816, see his Analysis of Weather Memorandum Book, Jan. 1817.

1TJ’s Analysis: “37.”

2Correct sum is 47.16. TJ’s Analysis, which gives average rainfall to three decimal places, renders the total as “47.218.”

3Preceding two words interlined.

Index Entries

  • Durham, N.Y.; meteorological observations in search
  • Hamlin, Amos; and meteorological observations search
  • Hamlin, Amos; letter to search
  • Jefferson, Thomas; Writings; Analysis of Weather Memorandum Book search
  • Jefferson, Thomas; Writings; Weather Memorandum Book search
  • meteorological observations; by A. Hamlin search
  • meteorological observations; by TJ search
  • Monticello (TJ’s Albemarle Co. estate); weather recorded at search
  • New York (state); meteorological observations in search
  • scientific instruments; thermometers search
  • springs; temperature of as climate indicator search
  • thermometers; TJ uses search
  • weather; cold search
  • weather; heat search
  • weather; rain search
  • weather; snow search
  • weather; temperature readings search
  • weather; TJ’s Analysis of Weather Memorandum Book search
  • weather; wind search
  • Weather Memorandum Book (Thomas Jefferson) search