To Robert Patterson
Washington April 17. 1802.
Your favor of the 12th. is duly recieved. mr Barnes will write by the present post to his friend mr Michael Roberts inclosing funds to enable him to pay the bill for the Hadley’s quadrant and thermometers, which I will pray you to direct the person from whom they are bought to have packed properly: but first to have a stand accomodated to the quadrant: for tho’ at sea the hand is the only thing which can counteract the motion of the vessel, on land a stand is more agreeable. but it should be so accomodated as to be readily detached. I presume one of the stands found ready made in the shops, with it’s ball & socket, can be made to answer by making only the fixed socket in addition to the other.
We are introducing your cypher into our foreign correspondences. but it often happens that we wish only to cypher 2 or 3. lines, or one line, or half a line, or a single word. it does not answer for this. can you remedy it?
If mr Peale can succeed in producing fresh from salt water by a filtering apparatus, it will be a valuable discovery. there are parts of the world where a want of pure water may render the separation of impurities by filtration of value, provided they are better separated, or more cheaply, than by distillation. but besides the utility of the immediate discovery, no discovery is barren. it always serves as a step to something else.
I shall leave this place for Monticello about a week after Congress rises to be absent about 3. weeks. I think they will rise about the last day of the month. Accept my best wishes and affectionate esteem.
PrC (DLC); at foot of text: “Robert Patterson esq.”; endorsed by TJ in ink on verso.