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"This distance should be thought of not as three inches but as a foot divided into inches and eighths of inches. It is noticed that this foot is divided with the zero on the inside, the inches running to the left and the feet to the right, so that dimensions given in feet and inches may be read directly, as 1 ft. 0 1/2"." —French, 1911

Scaling Drawing with Ruler

"This distance should be thought of not as three inches but as a foot divided into inches and eighths…