Archive of Collections

Details and Image

TypeModel No.MakerCountryConstruction
DateScale LengthArea of Use
W.F. StanleySheppard's Duodecimal Cubing
W.F. Stanley
25 cm
General Calculations

Notes: "The Sheppard slide rule was patented by F. H. Sheppard in 1878 and designed to calculate area and volume in either feet and inches, or in decimal feet. The scale layout at first appears very simple: three pairs of what we would now call A and B scales: 2-cycle logarithmic scales. However, the left side of each scale is divided duodecimally (into 12ths) and the right side is conventionally divided into 10ths. The Sheppard is effectively two slide rules mounted on top of each other, with the top slide rule solving for area, and the bottom slide rule using the result of that calculation as the starting point for calculating volume. No cursor was provided and none is needed as all calculations are between adjacent scales. Problems of volume are solved top to bottom, multiplying length times breadth times thickness, and reading the answer on the bottom scale. There are no markings on the backs of the slides, under the slides, or on the back of the slide rule body. W. F. Stanley carried the Sheppard “Cubing Slide Rule” in their catalog until at least 1930, and described it as, “Cubing Slide Rule, Shepard’s, with two slides, giving at sight square or cubic contents in feet and inches up to 100 cubic feet, specially designed for quantity surveyors, timber merchants, etc., with instructions for use.” It was available in both 12-inch and 22-inch versions. This is the 12-inch version, which actually measures 13.25 inches long. The slide rule is quite thick, 0.45”, and the body is made from a single piece of boxwood rather than a back plate with separate pieces for the stators glued down. There are numbers stamped on one end, presumably for keeping the body and stators for each individual slide rule together during production."

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