Water Meter Company v. Desper, 101 U.S. 332 (1879)
U.S. Supreme CourtWater Meter Company v. Desper, 101 U.S. 332 (1879)
Water Meter Company v. Desper
101 U.S. 332
1. While letters patent for a combination are not infringed if a material part of it is omitted, yet if a part which is only formally omitted is supplied by a mechanical equivalent performing the same office and producing the same result, they are infringed.
2. The courts in this country cannot declare that any one of the elements entering into such a combination is immaterial. They can only decide whether a part omitted by the alleged infringer is supplied by an equivalent device.
3. Reissued letters patent No. 5808, granted March 24, 1874, being a reissue of original letters No. 109,372 granted Nov. 22, 1870, to Phinehas Ball, and Benaiah Fitts, for an improvement in liquid meters, are not infringed by letters patent No. 144,747, granted Nov. 18, 1873, to Henry A. Desper, for an improvement in fluid meters.
The facts are stated in the opinion of the Court.