Appellants were convicted after jury trial of violating 18 U.S.C.A. § 1792 in that they conveyed from place to place within the United States penitentiary, Atlanta, Georgia, an explosive device designed to kill, injure or disable officers, agents, employees and inmates of such institution. We affirm.

*276 There is no merit in the assignments of error having to do with the failure to continue the trial and in the number of jury strikes allowed appellants in selecting the jurors and the alternate juror. The assignment of error arising from the use of a film showing a test of an explosive device substantially similar to the device in issue is also without merit. The weight of this evidence was for the jury under a proper cautionary instruction which was given. The contention that there was no proof that the penitentiary in question was a federal penal and correctional institution is unsupported.

Affirmed.