Titled "How To Use Decimal-Keeper Slide Rules," it is another of the instruction manuals Maurice L. Hartung wrote for Pickett & Eckel, Inc., a slide rule manufacturer based in Chicago and Alhambra, ...

Dietzgen ceased the production of slide rules around 1972. The arrangement of scales corresponds to those depicted in a 1960 instruction manual for the "Dietzgen Decimal Trig Type Log Log Slide Rule," ...