Odger's English Common Law

PATENT RIGHTS. 601
(i.) that he is the original grantee, or the duly constituted
assign of the original grantee, of letters patent
;
1 and
(ii.) that the defendant has infringed the right conferred
by those letters patent.
(i.) The plaintiff must in the first place prove his patent.
This he can do by putting in a printed or written copy or
extract, certified by the Comptroller of Patents and sealed
with the seal of the Patent Office. 2 A patent may be granted
to two or more co-owners jointly for an invention made by
one or some of them, 3 in which case each of them, in the
absence of any special agreement, may use and work the
patent for his own profit, 4 and each therefore may maintain
an action for its infringement. 5
If the plaintiff be not
the original patentee, he must formally prove the various
assignments by which the patent right has been transferred
from the original patentee to himself.
If the defendant has denied the novelty of the invention,
it was formerly held that the plaintiff must, in the first
instance, give some slight evidence of this by culling some
one conversant with the trade to state that the invention
was unknown before the letters patent were granted. But
the modern practice is that the plaintiff establishes a prima
facie case on this issue by proving his patent. He thus
throws the burden of proof on the defendant, who must show,
if he can, some prior use of the invention in this country, or
some prior publication in this country of some intelligible
description of the plaintiff's invention. 7 The production of
the letters patent is prima facie proof that they were rightly
granted, and that all facts existed necessary to bring the
case within section 6 of 21 Jac. I. c. 3. 8
1 One of several co-owners of a patent may sue alone for an infringement of
his right : Sheehan v. G. E. By. Co. (1880), 16 Ch. D. 69 ; and so may one of
several co-owners of a trade mark : Dent v. Turpin (1861), 30 L. J. Ch. 496.
2 S. 79 ; and see 8. 78.
3 S. 1.
' Steers v. Rogers, [1892] 2 Ch. 13.
6 Sheelian v. 6. E. My. Co. (1880), 16 Ch. D. 59 ; Van Gelder Co. v. Sowerby Bridge
Society (1890), 44 Ch. D. 374.
« Turner v. Winter (1787), 1 T. R. 602 ; but see Penn v. Jack (1866), L. B.
2 Eq. 314.
» See Harris v. Bothwell (1887), 36 Ch. D. at p. 427.
» Amory v. Brown (1869), L. K. 8 Eq. 663.