UNITED STATES SUPREME COURT DECISIONS ON-LINE

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.