Hammacher v. Wilson

This is a bill charging infringement of letters patent No. 169,931, granted November 16, 1875, to William E. Ulman, for an improvement in piano-forte pedals. The respondent admits the validity of the patent, and the infringement, but justifies under a license made to him June 1, 1877, by Jacob Ulman, who was then the owner of the letters patent. The complainants reply that the license was revoked and canceled August 13, 1880, by William F. Ul-man, who was then the owner of the letters patent, in accordance with the provisions of the license, and on account of failure by respondent to perform…