Samuel Blatchford, The Driven-Well Cases (123 U.S. 267…
“ It allows a patent to be granted only for an invention which was not in public use or on sale for more than two years prior to the application for the patent, subject to the defense of abandonment within such two years, which is also the requirement of section 61 of the same act; while section 37 of that act requires that a person, in order to have the right to use and sell, without liability, a specific thing made or purchased prior to the application for the patent, shall have purchased it of the inventor, or constructed it with his knowledge and consent. ”
