RARE AMERICAN ELLIPSOGRAPH — F. BOWLY’S INSTRUMENT FOR DESCRIBING ELLIPSES, c. 1870, signed “F. Bowly’s patent Jan¹y. 14, 1868.” This most unusual instrument is constructed with framework of beautifully grained tropical hardwood, and with linkages and fittings of brass and boxwood. When closed up it measures 16-1/4″ (41 cm) long and only 5/8″ x 1-7/8″ (1.6 x 4.8 cm) in overall cross section. The frame (whose form reminds one of a violin bow) has fixed point and index pointer for orienting and stabilizing on drawing paper, and the linkage terminates in a holder for pencil lead or ink pen (not present). A boxwood rule is graduated in half inches from 1 to 21, each divided in eighths, and has two sliding swivel clamps (for adjusting size and ellipticity) attached to an extending hardwood arm and to a sliding brass linkage respectively. The instrument is totally functional and in excellent condition throughout.
This unusual ellipsograph is the invention of Franklin Bowly of Winchester, Virginia. He claimed “The advantages of this instrument are, great simplicity of arrangement, expedition and convenience in its application, and accuracy with which it describes an ellipse of any desired proportions within wide limits of size, ..,” and in 1868 he was granted U.S. patent 73,290. Bowly recommended the instrument for draftsmen in general, using pen or pencil point, but also to cut glass for pictures frames, etc., using a diamond point! Period literature acknowledged the invention, e.g., in Knight’s American Mechanical Dictionary (1876). A beautiful example of this clever design, and the only one we have seen.
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David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at [email protected]
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