An article from the Master Weaver (1956) explaining how handweavers can identify common yarns. It reviews unreliable appearance and physical tests (luster, tensile strength, elasticity), then gives a step-by-step burning test and microscope test, with instructions for building a simple alcohol lamp and a cheap microscope setup. It identifies wool, silk, cotton, linen, hemp, jute, ramie, rayon, acetate, nylon, Orlon, metallics and fiberglass, and notes the limits of the tests for mixed or treated yarns.