David McClure (ca. 1784–1842), educator, was a lifelong resident of Philadelphia and a staunch supporter of temperance. Having served in a Pennsylvania volunteer artillery unit during the War of 1812, he taught mathematics and, from around 1813, operated a nautical and mathematical academy. McClure claimed that “a large proportion of Navy Officers have been under my instructions.” He was the author of several works, including a Report of the Survey of a Section of the River Delaware (Philadelphia, 1820) and A System of Education for the Girard College for Orphans (1838). A longtime advocate of the creation of what eventually became the United States Naval Academy at Annapolis, in 1839 McClure became professor of mathematics at its predecessor in Philadelphia. He was still serving in that capacity when he died of pneumonia (Pennsylvania Archives, 2d ser. [1880], 12:264, 266; McClure to James Madison, 7 Mar. 1815 [DLC: Madison Papers]; John Adems Paxton, The Philadelphia Directory and Register, for 1813 [(Philadelphia, 1813)]; Thomas Wilson, ed., The Philadelphia Directory and Stranger’s Guide, for 1825 [Philadelphia, 1825], 89; Desilver’s Philadelphia Directory and Stranger’s Guide, for 1835 & 36 [1835], 117; DNA: RG 29, CS, Pa., Philadelphia, 1820–40; Washington Daily National Intelligencer, 18 June 1832; Philadelphia Pennsylvania Inquirer and Daily Courier, 2 Oct. 1839; Callahan, U.S. Navy description begins Edward W. Callahan, List of Officers of the Navy of the United States and of the Marine Corps from 1775 to 1900, 1901, repr. 1969 description ends , 361; Philadelphia Inquirer, 22 June 1882; David F. Long, Sailor-Diplomat: A Biography of Commodore James Biddle, 1783–1848 [1983], 174–6, 180; Philadelphia North American and Daily Advertiser, 14 Apr. 1842).

The mathematical instrument was a “plotting table” (McClure to TJ, 19 Oct. 1820). Although the associated papers sent to TJ at this time have not been found, McClure provided illustrations and a detailed discussion of the apparatus in the appendix to his 1820 Report of the Survey of a Section of the River Delaware: “This instrument is similar to the common draft board, both as regards its frame, and the plan of fixing the paper for drawing. It may be made either square or oblong, and of any size, to suit the extent of the draught, and the degree of accuracy required. Round the frame, (Fig. 3) are graduated the degrees and quarters of a circle whose centre is in the middle of the instrument. A strip of narrow paper may be glued round the frame, to receive the marks of the degrees and quarters. But strips of brass or box-wood, let into the frame, for the graduated degrees, would be much more durable, though they are not so easily marked. This instrument may be made portable, by placing hinges on the two upper sides of the opposite corners, and on the inside of the remaining corners of the frame; and having the board for the paper composed of pieces” (pp. 40–4, with quote on p. 40 and illustrations after title page). McClure did not receive a federal patent for the device.