I have duly recieved your favor of July 6. and am glad you have turned your attention to the invention of means for surveying and platting at the same time. I have but occasionally looked at the subject as a desideratum; but never seriously aiming at it’s solution myself. the basis however of what has occurred to me is a four wheeled carriage, very light, the wheels to be like cotton spinning wheels & all other parts proportionably light. just over the bolt which connects the perch with the fore axle, suppose a machine fixed, so as to remain steadily in the direction of the perch, and the fore-axle made to govern a tracer which should draw on paper all the changes of angle and direction which the fore axle should commence. but as to the wheelwork & other contrivances necessary to effect this on paper, I never aimed at them. they are much more within your competence. I am afraid you will find the magnetic needle too weak and tremulous an agent to fulfill your views. Accept the assurance of my great esteem and respect

Th: Jefferson