This handheld electronic calculator was described by its maker as an “advanced slide rule.” It has an array of twenty-five sloping plastic keys. These may either perform the function indicated on the key or, if the F key is pressed first, perform a “secondary function” which is indicated above the key on the keyboard. With this combination of keys, the calculator performs not only the four arithmetic functions but computes natural and common logarithms and anti-logarithms, trigonometric and inverse trigonometric functions, square roots, roots and powers for any real numbers, and reciprocals. The number pi may be recalled and there are five memory keys. An on/off switch and a degree/radian switch are behind the keyboard. Behind them is an eight-digit fluorescent display with a sign indicator. A mark behind it reads: Rockwell. A mark along the front edge reads: ADVANCED SLIDE RULE 61R.
According to the instructions for the calculator, it has a sealed battery pack that is recharged by plugging a charger into a jack on the back edge of the calculator. This example lacks a charger. A sticker on the back gives operating instructions. Text near the bottom of the sticker reads: Microelectronics Product Division (/) Rockwell International (/) Anaheim, California 92803. Further text reads: Calculator Model 61R (/) Assembled in Mexico (/) U.S. and Foreign Parts. It continues: Ser [sic] (/) No. 139029.
The calculator has a plastic, cloth-lined carrying case marked on the front: Rockwell. Also in the case is a pamphlet entitled The Answer Book Owner’s Manual for Rockwell Model 61R Advanced Slide Rule Electronic Calculator. It is copyrighted 1974.
Compare the Rockwell 63R (1986.0988.163).
[Advertisement], Washington Post, September 23, 1974, p. A7. Rockwell 61R advertised as selling for $119.95.
[Advertisement], Chicago Tribune, December 4, 1975, p. A6. Rockwell 61R advertised as selling for $69.95.
[Advertisement], Statesville (N.C.) Record and Landmark,May 12, 1975, p. 3. Rockwell 61R on sale for $79.95
[Advertisement], Washington Post, July 1, 1976, p. B10. Rockwell 61R, regularly $59.95, on sale for $28.83.
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