Pickett 14 Military Duplex Slide Rule

This ten-inch aluminum linear slide rule is coated with yellow plastic and has a flat nylon indicator. The back of the base has LL1, LL2, A, D, LL3, and LL4 scales, with B, T, ST, S, K, and C scales on the slide. The left end of the slide is marked: MODEL 14 (/) U.S. The right end has the Pickett triangular logo used between 1958 and 1962. The style of the grooved stamped aluminum posts is also consisted with this timeframe.

The top front of the base has scales for "opposite angle" (sine) in both degrees and mils; the top bottom of the base has "Distance D" and A scales. The front of the slide has scales for apex angle (in both mils and degrees), tangent, sine-tangent, sine, and base. The top center of the base is marked: U.S. MILITARY SLIDE RULE.

Pickett & Eckel, Inc., of Chicago and Alhambra, Calif., made this instrument for computations related to the use of field artillery. It fits in an orange-red leather case that has the Pickett logo and US stamped in gold on the front and a metal loop on the back for suspension from a belt. The case is lined with white plastic. A white plastic "data strip" slides into a slot on the case. The strip contains diagrams and equations for trigonometric functions, traverse computations, azimuth and distance from coordinates, triangle computation, and the distance to an artillery target.

The case fits in a brown, black, white, and yellow paper box. The box and its insert are repeatedly marked: ALL METAL SLIDE RULE a rule for every need. The Pickett logo appears between the two segments of the mark. The end of the box once bore a paper tag: 1 UNIT - FSN - 7520 - 656 - 0660 (/) Slide Rule – Military, Field Artillery (/) With Data Strip and Case MIL-S-20195B (/) Mfg. Contr.; PICKETT & ECKEL, INC. Model No. 14.

The object comes from the Felsenthal Collection of computing devices. (See Felsenthal's company history with 1977.1141.02.) Donor Ben Rau suggested a date of 1965 for this slide rule, but it was probably made a few years earlier. Compare to the box collected with 1995.0126.02.

References: Accession File; Tom Bullock, "Pickett 14 U.S. military slide rule," December 8, 2009, http://www.tbullock.com/sliderule.html; Clark McCoy, "Highlights of the A. J. Boardman Collection of Pickett Slide Rules," Journal of the Oughtred Society 16, no. 2 (2007): 10–14.

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