"The MANNHEIM (Polyphase) and the

DUPLEX (Polyphase-Duplex) SLIDE RULES"

by: William Cox

Copyright 1917

This volume includes instructions for the 4041, 4053, old 4071 family, and 4088-3 slide rules. This edition also includes a supplement on trig functions.

"The Slide Rule" by William Cox, Copyrighted 1917

It is stated that these instructions are for slide rules numbers 4031 to 4056.

"The Polyphase Slide Rule" by William Cox, Copyrighted 1909

"THE "DUPLEX" SLIDE RULE" by William Cox

Illustrations of the 4065 and 4065T are shown.

"The Polyphase Duplex Slide Rule" by William Cox

An illustration of the 4088-2 is shown.

Supplement: "The Slide Rule and Plane Trigometery", by J. M. Willard