Conversion. Copper and brass processing. Many parts and products used by the Army and the Navy must stand up under severe service conditions. Here the strength of a specimen of brass is being determined. The results of these tests enables engineers to select metals that have the strength and stiffness needed for various machined parts for guns and equipment. This testing machine records the tensile of yield strength of a metal specimen--its resistance to being pulled apart. A specimen in the machine is pulled until it breaks, and the load necessary to break is recorded. A meter attached to the specimen measures the amount of stretching. Chase Copper and Brass Company, Euclid, Ohio. Sourced from the Library of Congress.