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"W. & L. E. Gurley, Troy, N.Y.
Telescope 18 inches long
"Of the different varieties of the leveling instrument, that termed the Y Level, has been almost universally preferred by American engineers, on account of the facility of its adjustment and superior accuracy." Thus declared Gurley in 1871. At that time, Gurley offered four different levels, with telescopes of 16, 18, 20, and 22 inches long. Since the signature of this level was engraved by hand, the level was made between 1852 when Gurley began in business, and 1876 when Gurley's new engraving machine was up and running. New, with tripod, this
level cost $110. It belonged to Bowdoin College.
Ref: W. & L. E. Gurley, Manual of the Principal Instruments used in American Engineering and Surveying (Troy, N. Y., 1871), pp. 197-118.