U.S. Supreme Court
Burt v. Evory, 133 U.S. 349 (1890)
Burt v. Evory
Argued December 10, 1889
Decided February 3, 1890
133 U.S. 349
APPEAL FROM THE CIRCUIT COURT OF THE UNITED
STATES FOR THE DISTRICT OF MASSACHUSETTS
The claim in letters patent No. 59,375, granted to Alexander F. Evory and Alonzo Heston, November 6, 1866, for an "improvement in boots and shoes" was for a manufactured article, and not for the mode of producing it, and, as it was merely a carrying forward of the original idea of the earlier patents on the same subject -- simply a change in form and arrangement of the constituent parts of the shoe, or an improvement in degree only -- it was not a patentable invention.
Not every improvement in an article is patentable, but the improvement must be the product of an original conception, and if it is a mere carrying forward or more extended application of an original idea, an improvement in degree only, it is not an invention.