A DIVERSITY OF SLIDE RULES
“KEL-CO CLASS CALCULATOR FOR THOROUGHBRED RACE HORSES,” American, c. 1975, 10″ (25 cm) plastic, with case and instruction booklet, fine but cursor stuck, very complex computations for the winning wager! $295.
“CHRONOPOSE EXACT DE CANNEVEL,” French, c. early 20th c., 7-1/2″ (19 cm), paper over wood with brass, one slide for exposure calculations, the other for actual exposing of photographic test strips, good with wear. $170.
THE “UNIQUE” LOG-LOG SLIDE RULE, English, c. 2nd quarter 20th c., 6-3/8″ (16 cm), celluloid over mahogany, slide and cursor, trig tables to reverse, good. $150.
COMPLEX CIRCULAR SLIDE RULE, American, c. 1940, 4-1/8″ (10 cm) diameter, printed on enameled aluminum both sides, with three rotating cursors, excellent. $250.
CLASSIC PLASTIC SLIDE RULE, American, c. 1950, copyright by Ecco Co., a diminutive 6-5/8″ (17 cm) long, with twin-sided cursor and scales. $95.
UNCOMMON KEUFFEL & ESSER SLIDE RULE, American, c. 1920, 10-5/8″ (27 cm), plastic laminate to mahogany, table to reverse, beveled linear rule, double-sided slide, cursor with unusual readouts atop and aside for the three logarithmic scales of singles, squares, and cubes, the latter along the side of the rule, very fine with good leather case. $350.
THE POST “VERSALOG” RULE, Japanese manufacture, “Hemmi,” model 1460 by The Frederick Post Co., 12-1/2″ (32 cm), plastic laminate to bamboo, highly complex, double sided, counting 23 scales, with cursors and original leather case, excellent. $330.
EARLY FOUR-SLIDE RULE, English, c. 1800, 12″ (30 cm), lovely hand stamped boxwood throughout, four sided with four sliders, the latter each with scales or constants or ratios on the inner surfaces, all to enable calculation of numerous mathematical functions and the volume content of partially filled vessels of various shapes, very fine. (10473) $595.
Ask the Dealer
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]