[A] use prohibited by the license is a use in defiance of the monopoly reserved by the patentee, and necessarily an unlawful invasion of the rights secured to him by his patent. The license would be no defense to a suit for infringement by a use in excess of its terms. The patentee has the exclusive right of use, except in so far as he has parted with it by his license. The essence of the monopoly conferred by the grant of letters patent is the exclusive right to use the invention or discovery described in the patent. This exclusive right of use is a true and absolute monopoly and is granted in derogation of the common right, and this right to monopolize the use of the invention or discovery is the substantial property right conferred by law, and which the public is under obligation to respect and protect.77 F. at 291.
