Archive of Collections

Details and Image

TypeModel No.MakerCountryConstruction
DateScale LengthArea of Use
"Slide Rules, Other"
"Spirule / SPIRULE Plotter, Protractor & Calculator"
The Spirule Co.
29 cm
Control Engineering

Notes: "Invented by Walter Richard Evans this Root-Locus calculating aid is for the direct measurement of plots, addition of angles by successive rotation of the arm with respect to the disk and the conversion of various quantities to angles by means of curves."

Image 1

Image 2

Image 3

Image 4

Image 5