111 Shure Brothers Reactance Slide Rule Paper. One side is used for calculation of resonant frequency problems, the other for capacitive and inductive reactance. 112 Yellow slide rule (made by Pickett) Model N902–ES, SimplexTrig. The slide rule had its origins in Napier’s 1614 development of logarithms. The first rule in which a sliding scale moved between two fixed elements was made in 1654. The indicator was introduced in 1778. 113 Large white slide rule (made by Keuffel and Esser Co., NY) 114 Circular slide rule (made by United Transformer Corp, NY) Paper. This slide rule can be used for all types of calculations,“particularly in the radio and communications fields.” 115 Circular slide rule and protractor Metal. Front says “Binary Slide Rule” Made in USA, Copyright 1940. Back says copyright 1931. |