Notes: "This Tavernier Gravet slide rule is a bit of a mystery. The gauge points along the lower vertical edge, marked with abbreviations in French, appear to be useful conversion factors specifically for engineering or construction: density of oak, iron, bricks, inch-cm length conversion, etc. See “Pocket Book of the Gauge Marks” by Panagiotis Venetsianos to figure them all out. It is not clear which scale these gauge marks work with. The frame of the cursor has three hairlines on that lower edge, at least one of which would work with the L scale that is below the gauge marks. Otherwise the scale layout is unusual but quite functional. On the front it is: A, DF | CF, CI, C | D, K. On the back of the slide there are Sine and Tangent scales and a B scale. There is a 25 cm ruler on the upper, beveled edge. The glass in the cursor is missing. The markings on the back are both clear (“Tavernier-Gravet Rue Mayet 19, Paris”, T-G was at this address from 1881 to 1939) and cryptic (“13 bis”, “Modele Depose”, and “12-26”)."
