Fond du Lac County v. May, 137 U.S. 395 (1890)
U.S. Supreme CourtFond du Lac County v. May, 137 U.S. 395 (1890)
Fond du Lac County v. May
Argued November 26, 1890
Decided December 15, 1890
137 U.S. 395
ERROR TO THE CIRCUIT COURT OF THE UNITED
STATES FOR THE EASTERN DISTRICT OF WISCONSIN
Letters patent No. 25,662, granted to Edwin May, October 4, 1859, for an "improvement in the construction of prisons," are invalid.
The novel idea set forth in the patent was to interpose a grating between
the jailer and the prisoners at every stage of opening and shutting a door. The mechanism of the patent, except the grating, was old.