This appeal is from a judgment for the defendant Commissioner of Patents in,a suit under R.S. § 4915, 35 U.S.C.A. § 63, to obtain reissue of a patent with added claims. Quite apart from any question of estoppel, there was no substantial evidence of the “inadvertence, accident, or mistake” required by R.S. § 4916, 35 U.S.C.A. § 64. We express no opinion regarding the District Court’s ruling that the appellant was, as a matter of law, estopped to make the added claims.

Affirmed.