A will is said to be proved in common form when the executor proves it on his own oath; as distinguished from “proof by witnesses,” which is necessary when the paper propounded as a will is disputed. Hubbard v. Hubbard, 7 Or. 42; Richardson v. Green, 61 Fed. 423, 9 C. C. A. 565; In re Stranb. 49 N. J. Eq. 264, 24 Atl. 569; Sutton v. Hancock, 118 Ga. 436, 45 S. E. 504