Clause 8. _The Congress shall have Power_ * * * To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries. Copyrights and Patents SCOPE OF THE POWER This clause is the foundation upon which the national patent and copyright laws rest, although it uses neither of those terms. So far as patents are concerned, modern legislation harks back to the Statute of Monopolies of 1624, whereby Parliament endowed inventors with the sole right to their inventions for fourteen years.[1157] Copyright law, in turn, traces back to the statute of 1710 which secured to authors of books the sole right of publishing them for designated periods.[1158] Congress was not, however, by this provision, vested with anything akin to the royal prerogative in the creation and bestowal of monopolistic privileges. Its power is limited as to subject matter, and as to the purpose and duration of the rights granted. Only the writings and discoveries of authors and inventors may be protected, and then only to the end of promoting science and the useful arts.[1159] While Congress may grant exclusive rights only for a limited period, it may extend the term upon the expiration of the period originally specified, and in so doing may protect the rights of purchasers and assignees.[1160] The copyright and patent laws do not have, of their own force, any extraterritorial operation.[1161] PATENTABLE DISCOVERIES The protection afforded by acts of Congress under this clause is limited to new and useful inventions,[1162] and while a patentable invention is a mental achievement,[1163] yet for an idea to be patentable it must have first taken physical form.[1164] Despite the fact that the Constitution uses the term "discovery" rather than "invention," a patent may not issue for the discovery of a hitherto unknown phenomenon of nature; "if there is to be invention from such a discovery, it must come from the application of the law of nature to a new and useful end."[1165] Conversely, the mental processes which are thus applied must display "more ingenuity * * * than the work of a mechanic skilled in the art";[1166] and while combination patents have been at times sustained,[1167] the accumulation of old devices is patentable "only when the whole in some way exceeds the sum of its parts."[1168] The Court's insistence on the presence of "inventive genius" as the test of patentability goes far back and has been reiterated again and again in slightly varying language,[1169] although it seems to have had little effect on the point of view of the Patent Office.[1170] PROCEDURE IN ISSUING PATENTS