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In 1881, Edwin Thacher, an American bridge engineer patented this cylindrical slide rule, 4 inches in diameter and 18 inches long. In 1882, scales were divided for Thacher's instrument by W. F. Stanley of London.

The cylindrical rule can be both…

The globe, presumably of pasteboard covered with plaster of Paris, has a map of twelve gores printed from engraved plates and colored. The globe is set upon a polar mounting above a calendar plate, which represents the elliptic circle. However, the…

This armillary sphere is for demonstrating the phenomenon of the seasons of the year and to show either the real motion of the earth or the apparent motions of the heavens. The outer frame consists of two meridian rings marked with degrees of…