Section 4927. The Commissioner shall, at the time and place designated in the published notice, hear and decide upon the evidence produced, both for and against the extension; and if it shall appear to the satisfaction of the Commissioner that the patentee, without neglect or fault on his part, has failed to obtain from the use and sale of his invention or discovery a reasonable remuneration for the time, ingenuity, and expense bestowed upon it, and the introduction of it into use, and that it is just and proper, having due regard to the public interest, that the term of the patent should be extended, the Commissioner shall make a certificate thereon, renewing and extending the patent for the term of seven years from the expiration of the first term. Such certificate shall be recorded in the Patent-Office; and thereupon such patent shall have the same effect in law as though it had been originally granted for twenty-one years.

Operation of Extension

Section 4928. The benefit of the extension of a patent shall extend to the assignees and grantees of the right to use the thing patented, to the extent of their interest therein.