Appleton's dictionary of machines, mechanics, engine-work, and engineering : illustrated with four thousand engravings on wood ; in two volumes (1873)
D. Appleton and Company · New York : D. Appleton and Co. · leaf 533
e sphere,and the plane of projection is a plane which touches the sphere at any point assumed at pleasure. The 526 PROVIXG MACHINE, HYDROSTATIC. point of contact is called ihe principal point; and the projections of all other points on the sphere areat the extremities of the tangents of the arcs… … [Kl
Mechanical engineering · Mechanics · Engineering
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