SIR: In the matter of the enrolled bill (S. 691) extending letters patent of Edward A. Leland, I have the honor to report that said letters patent were granted for an improved paint can August 14, 1860, for the term of fourteen years; that they consequently expired on the 14th day of August, 1874, whereupon the invention became the property of the public.
The present act proposes to extend the term of the patent seven years from said 14th day of August, 1874, and give to it the same effect in law as if it had been originally granted for the term of twenty-one years.
It will be seen, therefore, that those who have innocently used and purchased the invention since the expiration of the letters patent on the 14th of August, 1874, under the impression that the invention was the property of the public, will, by the retroactive terms of the bill, be liable for damages for such use upon suits for infringement.
This hardship is generally, if not always, provided against by a proviso to such bills, setting forth in terms "that no person shall be held liable for the infringement of said patent, if extended, for making use of said invention since the expiration of the original term of said patent and prior to the date of its extension."
Unless such a proviso is incorporated into the present bill, the injustice alluded to may be done.
Very respectfully, your obedient servant,
ELLIS SPEAR,
Commissioner of Patents.