This small pamphlet consist of fifteen rectangular sheets of paper cut from a blueprint and stapled together on the left side. It has drawings and formula for the solution of right angled triangles, as well as tabulated values of openings required for plugs of differing sizes and different angles of opening. The pamphlet was owned by machinist and museum specialist George A. Norton. It may date from the time he worked as a machinist in the Washington Naval Gun Factory.
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