The M. Zwicky Sons Soap Company was brought to Springfield, Illinois from Madison, Wisconsin in 1890 by George Zwicky and his brothers Casper and Michael, Junior. Michael Zwicky Senior had established the M. Zwicky Soap Manufacturing Company in Wisconsin, and he ran it until his death in 1876. The Zwicky Sons carried on the business until moving to Springfield. Casper Zwicky died in 1894, bequeathing his part of the company to George. Michael Zwicky Junior sold his interest in the company to George in 1896, leaving George as the sole proprietor of the business. George Zwicky continued in business until 1905 when he retired. The soap factory was located at the northwest corner of First and Madison Streets. The company’s best recognized product was known as the “U.S. Navy Floating Soap.” George Zwicky originated the idea for floating soap.
The collection includes the military, naturalization, cemetery, and last will and testaments documents of the Zwicky family. Also news articles about the soap company, business agreements, and notebooks of soap recipes, experiments, container measurements, and customer lists.