1To Thomas Jefferson from David Rittenhouse, 25 June 1790 (Jefferson Papers)
Since my last letter (and not before) I have read Mr. Whitehursts Book on the Subject of Measures. Amongst the many different ways of obtaining the Same End, the Method proposed by him seems to be a very good one. I see no reason to object to the lenghth he has assigned from experiments, to a pendulum vibrating seconds in the Latitude of London Vizt. 39.1196 inches. You Suppose (page 4.) the...