William Lambert (d. 1834), astronomer, was a native Virginian who became acquainted with TJ as a State Department clerk, 1790–92. He regularly informed TJ of his new calculations throughout the latter’s retirement and established the longitude of Monticello. Lambert served as a clerk in the House of Representatives and in the pension section of the War Department, temporarily losing the former position late in the 1790s because of his passionate Republican views. He devoted most of his spare time to proposals for building a national astronomical observatory and establishing an American prime meridian in Washington. For years Lambert vainly sought congressional support for these plans while fruitlessly seeking better government positions and complaining that his enemies were frustrating his professional and scientific efforts. In 1818 he helped found and played a leading role in the Columbian Institute for the Promotion of Arts and Sciences (PTJ description begins Julian P. Boyd, Charles T. Cullen, John Catanzariti, Barbara B. Oberg, and others, eds., The Papers of Thomas Jefferson, 1950– , 31 vols. description ends , 26:234–5; Lambert to TJ, 15 Dec. 1804 [DLC]; Silvio A. Bedini, The Jefferson Stone: Demarcation of the First Meridian of the United States [1999]; Annals description begins Annals of the Congress of the United States: The Debates and Proceedings in the Congress of the United States . . . Compiled from Authentic Materials, Washington, D.C., Gales & Seaton, 1834–56, 42 vols. All editions are undependable and pagination varies from one printing to another. Citations given below are to the edition mounted on the American Memory website of the Library of Congress and give the date of the debate as well as page numbers. description ends , 11th Cong., 2d sess., 1660–1 [28 Mar. 1810]; Lambert to James Madison, 26 Apr. 1812 [DNA: RG 59, LAR, 1809–17]; Washington National Intelligencer, 21, 23 Oct. 1834).