the stars with the plane, or face of the instrument both East and West. USNM 152079. FIGURE 80. RITTENHOUSE & EVANS, Philadelphia, Pa., 18th century. _Surveying Compass_, about 1780, made of brass, overall length 13-3/4 in., diameter of dial 5-1/4 in., silvered bubble level, vernier on alidade. The glazed dial, engraved "Rittenhouse & Evans," is fitted with a brass cover. This instrument was made during a brief partnership between David Rittenhouse and David Evans, a clock- and watchmaker of Philadelphia and Baltimore. It was one of several owned and used by John Johnson in 1818 for surveying the boundaries between Canada and Maine. The survey, made in compliance with the Treaty of Ghent, is described in _The Collections of the Maine Historical Society_ (Portland: Hoyt, Fogg & Donham, 1881, vol. 8, p. 20): Thomas Barclay, of whom we have heard more than once before, as a Commissioner under the treaty, on the part of Great Britain, and Cornelius P. Van Ness, on the part of the United States, were appointed Commissioners to ascertain and run the line. An actual survey was arranged, and surveyors appointed, to wit: Charles Turner, Jr., on the part of the United States, and Colin Campbell on the part of Great Britain. About twenty miles of the line was surveyed, then the work was discontinued, never to be resumed; but an exploring survey was commenced by Colonel Bouchette, on the part of Great Britain, and John Johnson, on the part of the United States. These gentlemen made an exploring line in 1817, extending ninety-nine miles from the monument at the head of the river St. Croix, and made separate reports of their doings. In 1818 Mr. Johnson, with Mr. Odell, who had taken the place of Col. Bouchette, finished running the exploring line to the Beaver or Metis River.... [Illustration: Figure 80.--Zenith sector, with a radius of 19 in., constructed by David Rittenhouse for Andrew Ellicott. USNM 152079.] [Illustration: Figure 81.--Brass surveying compass marked "Rittenhouse & Evans," about 1780. Over-all length, 13-3/4 in.; diameter of dial, 5-1/4 in. This instrument, made about 1780, was owned and used by John Johnson in 1818 for surveying the boundaries between Canada and Maine. USNM 309543.] Gift of John Johnson Allen of Burlington, Vt., in 1927. USNM 309543. FIGURE 81. THOMPSON, Captain SAMUEL ROWLAND (18th century); Lewes, Del. _Octant_ made of dark wood and with lignum vitae; brass fittings. This harbormaster's instrument, used by Captain Thompson during the second half of the 18th century, is without numerical designations on the arc. The eighth part of a circle is connected to an apex by two side pieces with a swinging arm hinged at the apex, with a blade at its end that moves along a checkered scale on the arc. Gift of George Andrews Thompson of Baltimore, Md., in 1926. USNM 308473. VOIGHT, HENRY (1738-1814), Philadelphia, Pa.