nt is an addition to, or change in, a known art, machine,
manufacture or composition of matter, which produces a useful result
and is patentable if it amounts to invention. Lastly "a patentable
design may consist of a new and ornamental shape given to an article
of manufacture, or of an ornamentation to be placed upon an article of
old shape." It is said that the law relating to this subject intends
that the patentability of a design shall be determined by its appeal
to the eyes of the ordinary man, and not to the eyes of a jury of
artists. Design patents are granted for different periods, three years
and a half, seven years and fourteen years, as the applicant may
elect.

The subject matter of a patent must be new and useful. It must be new
not only to the patentee, but to all the people in this country, and
at the time he filed his invention. The federal law, however, secures
a patentee who had no knowledge that his invention had been discovered
abroad and which had not been patented there, nor described in a
printed publication. Before the enactment of this law a patent was not
granted without showing that the applicant was the original inventor
with relation to every part of the world.

Much has been said concerning the novelty of an invention. This may be
in the use of an old means in a new way; or a change of shape or form
to produce new functions and results, but the changes must amount to
invention, which is more than mere novelty.

A foreign patent in order to invalidate an American patent must
antedate the invention patented. A foreign patent exists as a patent
only as of the date when the invention was published. In England an
invention is not patented within the meaning of the act of Congress
until the enrollment of the complete specification.

What is meant by a prior publication? It is a printed book, newspaper
or document of a public nature disclosing the invention intended and
actually employed for the purpose of informing the public. Publication
in a book of general circulation is sufficient; business catalogues or
circulars are not such publications as are meant in the law.

To defeat a patent on the ground of want of novelty the proof of prior
use or knowledge must be convincing, sufficient to establish the fact
beyond a reasonable doubt. The recollection of one witness concerning
the peculiar construction of a piece of machinery, especially if the
structure is one of complex character, is not en