The procedure starts with rough ground specimen. Grinding is in two stages on iron laps designed to maintain a flat surface as the lap wears. Polishing is done on a lead lap. The construction and operation of the machines are described and grades of abrasives and special mixtures of oils are given. Grinding and polishing can be done with specimen held in the hand. A supplementary device holding a mounted specimen mechanically permits high pressure for polishing and greatly reduces polishing time for hard materials. The grinding methods are effective in making thin sections.

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