7.10 Vector Hyperbolic Rules
The members of this special group contain scales of hyperbolic trigonometric functions that are used in conjunction with regular trigonometric scales to perform calculations of vector quantities. The first of this type of vector slide rule was the K&E Model 4093-3 in the late 1920’s. Their model 4083-3 and 4083-5 followed, as did new rules by other manufacturers. Details of the use of these scales are provided in the section Vector/Hyperbolic Calculations. The Collection presently has 11 slide rules that can be classified as vector rules.
Note that the Sun-Hemmi Model 153 is included here as it had special scales from which hyperbolic function values could be determined directly. This very special rule and its scales are described in the vignette Hemmi 153 Scales.