ed 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

The standard of patentability is a constitutional standard, and the
question of the validity of a patent is a question of law.[1171]
Congress may authorize the issuance of a patent for an invention by a
special, as well as by general law, provided the question as to whether
the patentees device is in truth an invention is left open to
investigation under the general law.[1172] The function of the
Commissioner of