1To Thomas Jefferson from David Rittenhouse, 28 September 1785 (Jefferson Papers)
That I have so long delayed acknowledging your favours has been owing to my absence from home....
2To Thomas Jefferson from David Rittenhouse, 26 June 1786 (Jefferson Papers)
Your favour of Jan. 25th. I received some time ago, and likewise all the Nautical Almanacs you...
3To Thomas Jefferson from David Rittenhouse, 14 April 1787 (Jefferson Papers)
About the latter end of June last I sent you the 2d. Vol. of our Transactions, directed to Mr....
4To Thomas Jefferson from David Rittenhouse, 8 November 1788 (Jefferson Papers)
About two Months ago I received your very valuable present of Books, mentioned in the last letter...