09-002. American, copyright dated 1953, and manufactured by The Gerber Scientific Instrument Company, 162 State Street, Hartford 3, Connecticut. The apparatus is described in the instruction manual as an easy-to-use, manually operated graphical-numerical computing device. It can be used to perform computations directly on graphs, curves, recordings, and is used on graphical work where reading, plotting and interpolating is of the essence. It has two springs - a calibrated triangular spring and a number spring. Both are fixed at the left ends and are attached at the right end to a slide. The calibrated triangular spring is used directly in linear computations such as: multiplying curves by constants or by variables directly; for interpolating between families of curves; or for the plotting of test points. The main body of the apparatus is 14 1/8" long x 5 1/8" wide and made of black anodized aluminum, with 18 scales - linear, reciprocal, trigonometric, logarithmic, probability, etc. This unusual computing device is in very good overall condition, in its original plush lined leatherette case.
