both sides. It was a thin sheet of canvas coated with heatand pressure-treated gum rubber roughly 6 ½ x 3 ½ feet in dimensions. The rubber blanket was light and weighed only about 40 ounces. It was a standard item of Union issuance beginning in November 1861. Charles Goodyear patented the process for vulcanizing rubber in 1844, and the patent was extended by a licensee, Union India Rubber Company of Middletown, Connecticut, in 1858. This created a virtual monopoly for Union India Rubber as far as the “manufacture of rubber goods for military purposes.” The seven-year duration of the patent meant that Union India Rubber Company dominated the trade for almost the entire Civil War. They aggressively enforced their patent rights through the courts, and their company and its subsidiaries managed almost $6 million in Union contracts from 1862 to 1864. The pressure of government orders led Union India Rubber Company to open a second plant in nearby Naugatuck (later called The Phoenix Rubber Company) to manufacture gum rubber blankets beginning in 1863.
A number of other manufacturers produced gum rubber blankets and ponchos despite the potential patent infringement lawsuits. In one such incident, Providence (a/k/a National) Rubber Company attempted to break the
GUM BLANKET Vulcanized Rubber in the Civil War
By Craig L. Barry
he vulcanized rubber ground cloth, or “gum blanket”, was a straightforward and utilitarian piece of equipment that was greatly prized by soldiers on Union India Rubber Company’s monopoly by filling a large U.S. Government contract for gum rubber blankets for Schuylkill Arsenal. Union India Rubber filed suit for patent infringement and won damages of over $200,000, “… in spite of which it is believed it (Providence) still found its business in blankets profitable.” As a result of the potential for profit, there was quite a bit of patent
