Four adding machines were stolen from an interstate shipment. Jurisdiction concerning the misdeed was thereby accorded to the United States District Court under an indictment charging the appellant with a violation of 18 U.S.C. § 659. A trial by jury resulted in a conviction. The issue on this appeal is the sufficiency of the evidence to establish the appellant’s possession of the stolen property. All of the machines were located and possession was traced directly to the appellant.

We have examined the evidence produced by the United States and find that it was sufficient to present a jury question. The weight of the evidence and the credibility of the witnesses are issues of fact for the jury and a verdict will be sustained if it is supported by evidence which is substantial when viewed from its aspect most favorable to the Government. Pederson v. United States, 392 F.2d 41 (9th Cir. 1968).

Even assuming, arguendo, that there could be a question of sufficiency *389 of competent evidence, no objection was raised at the trial to admissibility based upon competency. Errors with respect to admissibility of evidence not raised in the trial court may not be considered for the first time on appeal. Keegan v. United States, 385 F.2d 260, 264 (9th Cir. 1967). There was nothing here which might be called plain error.

The judgment is affirmed.