Section 4904. Whenever an application is made for a patent which in the opinion of the Commissioner, would interfere with any pending application, or with any unexpired patent, he shall give notice thereof to the applicants, or applicant and patentee, as the case may be, and shall direct the primary examiner to proceed to determine the question of priority of invention. And the Commissioner may issue a patent to the party who is adjudged the prior inventor, unless the adverse party appeals from the decision of the primary examiner, or of the board of examiners-in-chief as the case may be, within such time, not less than twenty days, as the Commissioner shall prescribe.

35 Electric R. Co. vs. Jamaica, etc., R. Co., 61 Fed. Rep., 655.

36 Heath vs. Hildreth, Mac. A. Pat. Case 12,11 Fed. Cas. No. 6, 309.

37 Chandler vs. Todd, Mac. A. Pat.

Cas., 493, 5 Fed. Cas. No. 2, 593

38 Singer vs. Braudsdorf, 7 Blatcf.

(U. S.), 521, 22 Fed. Cas. No. 12, 897.

An interference means a dispute on the question of priority of invention.39 A failure to declare an interference is not conclusive.40