Signedin black lettering along center bar: KEUFFEL & ESSER Co.
in white lettering on red background on label on green storage case: K & E CO.
Inscribedin black lettering along center bar: 1631P / N.Y. PARAGON
in black lettering on white background on label on gree case: PARAGON TRIANGULAR SCALE / REG. U.S. PAT. OFF. / 1 ONLY 1631P 12 IN. / MADE IN U.S.A. REG. U.S. PAT. OFF.
FunctionTriangle rulers are used for measuring and drawing straight lines in various plane scales. They are particularly useful for engineers, architects, and draftsmen for providing numerous measures at once. Blueprints, and other design schematics are not drawn to scale and these rulers make it easy to determine the actual length of represented lines with minimal calculations.
Primary SourcesCatalogue of KEUFFEL & ESSER CO. Manufacturer’s and Importers, Drawing Materials, Surveying Instruments, Measuring Tapes, 39th edition, 1887, p. 221 - 222.
ProvenanceRuler was owned by William R. Osgood (Engineer, Harvard class of 1917). The ruler was donated by his nephew Theodore K. Osgood on November 20, 1997.