International Workshop AN Bart Depuydt's strange Hemmi slide rule J. Hemmi “Sun” Model 82 Pocket Click images for magnification Bart's Hemmi ISRM's Hemmi Data: Length 150 mm Probably used by an English schoolkid According to the ISRM: made between 1914 and 1929 Question: Why do the slots on the back differ from all Hemmi's shown in the ISRM?
