Gerber GA-103 GraphAnalogue
Country of manufacture: USA,            Date of manufacture: ____
Overall length: 39.2 cm,          Width: 15,5 cm,           Thickness: 2.0 cm           Weight: _____ gms.
Materials & Construction: Black aluminum rectangular base with grooves near its top and bottom long edges. A rectangular aluminum plate is screwed to the center of the base. A semi-cylindrical piece of clear plastic runs along the length of the top edge of the base, and is attached to silver aluminum end caps at either end of the base. A silver aluminum runner moves to left and right along the base's two grooves. Screwed to the left side of the runner is a clear plastic rectangle with a vertical indicating line. Two springs are attached to the left end cap and left side of the runner and sit beneath the semi-cylindrical plastic piece. The top spring is triangular, with every fifth coil colored. The bottom spring is circular, and has white labels on five of its coils: 0, 2, 4, 6 (which is missing on this example), 8, 10. The springs stretch and contract together when the runner is moved to right and left. (Description taken from the Harvard Collection of Historiical Scientific Instruments, here. For a more complete discussion and instructions for use, see Lovett, Rod, The Gerger GraphAnalogue, UKSRC Slide Rule GAZETTE ISSN 1472-0000, Colin Barnes Memorial Issue, Autumn 2016, pp 27-33.
Scales: 18
RI Reciprocal Inch, RF Reciprocal Foot,
RC Reciprocal Centimeter, I Linear scale w/values 1 - 10, F Linear scale w/values 0.1 - 0.8, CM Linear scale w/values 3 - 25, T Tangent scale w/values 6° - 45°, T Tangent scale w/values 45° - 84°, S,Co Sine and Cosine scales, D Degree scale w/values 10 - 90, ( )² Square scale w/values 1 - 3.1, ( )² Square scale w/values 3.2 - 10, ( )½ Square root scale w/values 1 - 100. ( )⅓ Cube root scale w/values 1 - 1,000, L10 Logarithm base 10, Le Logarithm base e scale w/values 1.11 - 2.7, Le Logarithm base e scale w/values 3 - 20,000, P Probability scale
Condition: C4-C5 (Minimal to Normal signs of use)
Came with: Brown leather covered case