The BRUSH DEVELOPMENT CORP., which became the world's largest producer of artificially grown piezo electric crystals, was organized in 1930 to market electronic devices utilizing the crystals, which had been developed in the Brush Laboratories. Located at E. 40th St. and Perkins Ave., the company, under the direction of president Alfred L. Williams, sold a wide range of products, including high-fidelity microphones and speakers, a practical application of the piezo electric principle. Brush transmission equipment found a ready market in the rapidly growing radio broadcast industry, and was used by Admiral Richard E. Byrd on his second Antarctic expedition in 1934. The firm also offered several products in the magnetic recording field. It was the sole producer of the piezo electric hearing-aid receiver and marketed a sound mirror to aid in voice training. The Brush BK 401 Sound Mirror (1946) was the first tape recorder to be designed and built in the United States. The Brush oscillograph, which recorded electrical impulses on paper, was widely used by the medical profession. The company also produced a self-contained Mail-A-Voice magnetic recorder popular among servicemen during World II, which was adapted for use as an office dictating machine—its professional model, with foot pedal, retailed for $97 in 1947. Brush Development Corp. was purchased by CLEVITE CORP. for $7 million in 1952 to diversify its product line.
Charles Baldwin Sawyer Papers, Freiberger Library, CWRU.