S: Carolina—. St Helena
Jany. 19th. 1806
Knowing the pleasure you derive from a Communication of improvements or discoveries—induce me to intrude upon some of your leisure moments, if any, at this busy Season, to communicate what I concieve to be new & may, possibly, be of use to our Goverment—a disagreeable passage of 48 days from Philaa. to Savannah, on board a leaky and dismasted vessel, induced me to view in a bad light the uncertainty of our present mode of obtaining an accurate knowledge of our Latitude, by being obliged to have some Education more than Simple reading & writing & a small show of mathematical knowledge.—and viewing the disadvantages of vision in 18 passages, the difference of vision, between Captains & mates—never having Seen them observe alike with Hadly’s Quadrant—induced me to think of a more simple mode of observation—. I thought of one, but upon mature consideration, I found would not answer nautical purposes, on account of the impossibility of keeping the machine in a horizontal position, from the undulation of the Waves—Yet not willing to lose the use of the Machine induced me to think of applying it to the Earth—I have not an oppertunity of Experimenting upon it on account of my situation & not having workmen Capable of Exicuting the work in this Southern Country—To goverment it may be of use in ascertaining its Boundaries—I am sorry I have not an oppertunity of Getting one made, as it requires much accuracy to exicute it;—It will be necessary to have Moores Tables of declinations—the following drawing will Give you a better Idea of the machine
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This machine might be made very small—the Size had better be left to the Judgement of the employed—Figure 1 is the half of a square made of brass—No. 1 is a scale of the Suns Greatest altitude—No. 2 is a scale of the Suns declination, which is moveable & sliding upward or downwards according to the suns declination, having a hole through its upper part at 6 for the Rays of sun to pass, & fall upon a scale of Latitude at any part of 3.—By this means no deduction need be made for declination—when the light falls to the most northern parts of the machine, when bearing nearly N. & S. you have the Exact latitude No. 4 is a needle which shews the position the machine must be placed in—No. 5 is a tube filled with water or Mercury; commonly called a leveller to level the machine—another machine that may be folded & put into the pocket is as follows.
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If Either answers the purpose I shall be pleased & if they may be of service to my Country I shall be flattered—As an american I cannot be otherwise than Interested—these Ideas lead to a subject which I concieve to be of some Importance to the U:S:—on this Island are an immense Quantity of live oak timbers Cut for frigates &c About 4 Years since and now lying to Rot—Particularly in Mrs Chaplains wood that are perhaps Rotten, they were the Best & in Consequence of their weight, being meant for heavy vessels not carried to the landings—a large Quantity, Engaged of Mrs. Burcogne & Scott lies at Burcogne’s landing—such Pieces that are in the Salt mud are good—those upon the high land are splitting & Rotting—they are valuable & distresses me to see such valuable materials daily decaying—it is bad Policy to Engage the Proprietors here to sell & never be paid for their property—at a future time they may be backward in Engaging with the Contractors—not one having recieved one single Cent for their trees—Goverment is not to blame—they pay contractors & they do not pay the planters—
I beg leave to mention another article which is new—The Pride of China or India is a tree you have in abundance—at least in virginia, N: Carolina, S. Carolina & Georgia it is as hansome as mahogany & when used as Bedstead are never incomoded by bugs—
With Sentiments of respect I remain Your obedient Servant
ViW: Jefferson Papers, Tucker-Coleman Collection.