Finding Aids

Fred C. Ielfield (1864-1948) was a mechanical engineer and inventor. This collection consists of twelve patents for mail canceling and postmarking machinery, corn-husking machinery, and a cereal cutter, all invented by Ielfield.

Michael Somerville Withers (1926-1985) was a mechanical engineer and an inventor. He worked at the DuPont Company from 1953 to 1983. Withers is the holder/co-holder of fourteen United States patents for plastic laminates and heat exchangers. Withers's papers document his career with the DuPont Company on plastic laminates, heat exchangers, and seal rings. The papers are organized into seven series: Sabine River Works; Experimental Station; Nafion Laminator; Heat exchangers/heaters; Vespel seal rings; Pneumatic tension device; and Trade catalogs, pamphlets, and articles.

Penrose Robinson Hoopes (1892-1976) was a mechanical engineer, inventor, author, and horologist. He specialized in the design of factory equipment, particularly high-production automatic machinery. This collection consists of documents pertaining to Penrose R. Hoopes' career as an engineer and inventor. Hoopes' work includes machine designs for the American Chicle Company, Campbell Soup Company, Johnson and Johnson, and the Ferracute Machine Company. The bulk of the collection material spans from 1923 to 1968, with some patent material and typescript excerpts from the eighteenth and nineteenth centuries. The collection includes correspondence and blueprints related to Hoopes' work as a designer and inventor, as well as employee records, manuscript material, photographs, trade pamphlets, and bibliographic information.

William M. Henderson (1831-1904) was a mechanical engineer and inventor who spent most of his career in Philadelphia. The papers consist of two items: a scrapbook, which pertains to Henderson's career and inventions, and an atlas of twenty-nine plates of Bessemer and rolling-mill machinery.