An “exponential” slide rule

An “EXPONENTIAL” slide rule eveloped to facilitate problems involving the logarithms or antilogarithms of numbers. It differs from the ordinary slide rule of logarithms in two fundamental respects: (1) natural logarithms (to the base e = 2.71828) are given, and (2) both the characteristic and mantissa are determined directly in one reading. Logarithms of numbers from 0.00001 to 100,000, and the corresponding antilogarithms are given. As the addition of the characteristic normally would reduce the accuracy of the rule, the scale of logarithms has been split up into five 10-in. sections, thus giving an accuracy comparable with that of the ordinary rule. This exponential slide rule was developed by L. B. Sklar (A ´30) 816 North 6th Street, Philadelphia, Pa.