In giving to authors the exclusive right to dramatize any of their works, Congress did not exceed its powers under this clause. Even as applied to pantomime dramatization by means of silent motion pictures, the act was sustained against the objection that it extended the copyright to ideas rather than to the words in which they were clothed.[1176] But the copyright of the description of an art in a book was held not to lay a foundation for an exclusive claim to the art itself. The latter can be protected, if at all, only by letters patent.[1177] Since copyright is a species of property distinct from the ownership of the equipment used in making copies of the matter copyrighted, the sale of a copperplate under execution did not pass any right to print and publish the map which the copperplate was designed to produce.[1178] A patent right may, however, be subjected, by bill in equity, to payment of a judgment debt of the patentee.[1179] POWER OF CONGRESS OVER PATENT RIGHTS Letters patent for a new invention or discovery in the arts confer upon the patentee an exclusive property in the patented invention which cannot be appropriated or used by the Government without just compensation.[1180] Congress may, however, modify rights under an existing patent, provided vested property rights are not thereby impaired,[1181] but it does not follow that it may authorize an inventor to recall rights which he has granted to others or reinvest in him rights of property which he had previously conveyed for a valuable and fair consideration.[1182] Furthermore, the rights which the present statutes confer are subject to the Anti-Trust Acts, though it can be hardly said that the cases in which the Court has endeavored to draw the line between the rights claimable by patentees and the kind of monopolistic privileges which are forbidden by those acts exhibit entire consistency in their holdings.[1183] STATE POWER AFFECTING PATENTS AND COPYRIGHTS Nor do the patent laws displace the police or taxing powers of the States. Whatever rights are secured to inventors must be enjoyed in subordination to the general authority of the State over all property within its limits. A statute of Kentucky requiring the condemnation of illuminating oils which were inflammable at less than 130 degrees Fahrenheit, was held not to interfere with any right secured by the patent laws, although the oil for which the patent was issued could not be made to comply with State specifications.[1184] In the absence of federal legislation, a State may prescribe reasonable regulations for the transfer of patent rights so as to protect its citizens from fraud. Hence a requirement of State law that the words "given for a patent right" appear on the face of notes given in payment for such right is not unconstitutional.[1185] Royalties received from patents or copyrights are subject to a nondiscriminating State income tax, a holding to the contrary in 1928 having been subsequently overruled.[1186]