Mr. Chief Justice Waite delivered the opinion of the court.

The assignments of error, when grouped, present the following questions:—

1. Was the indictment bad because found by a grand jury of less than sixteen persons?

2. Were the challenges of certain petit jurors by the accused improperly overruled?

3. Were the challenges of certain other jurors by the government improperly sustained?

4. Was the testimony of Amelia Jane Schofield, given at a former trial for the same offence, but under another indictment, improperly admitted in evidence?

5. Should the accused have been acquitted if he married the second time, because he believed it to be his religious duty?

6. Did the court err in that part of the charge which directed the attention of the jury to the consequences of polygamy?

These questions will be considered in their order.

1. As to the grand jury.

The indictment was found in the District Court of the third judicial district of the Territory. The act of Congress ''in relation to courts and judicial officers in the Territory of Utah,'' approved June 23, 1874 (18 Stat. 253), while regulating the qualifications of jurors in the Territory, and prescribing the mode of preparing the lists from which grand and petit jurors are to be drawn, as well as the manner of drawing, makes no provision in respect to the number of persons of which a grand jury shall consist. Sect. 808, Revised Statutes, requires that a grand jury impanelled before any district or circuit court of the United States shall consist of not less than sixteen nor more than twenty-three persons, while a statute of the Territory limits the number in the district court of the Territory to fifteen. Comp. Laws Utah, 1876, 357. The grand jury which found this indictment consisted of only fifteen persons, and the question to be determined is, whether the section of the Revised Statutes referred to or the statute of the Territory governs the case.

By sect. 1910 of the Revised Statutes the district courts of the Territory have the same jurisdiction in all cases arising under the Constitution and laws of the United States as is vested in the circuit and district courts of the United States; but this does not make them circuit and district courts of the United States. We have often so decided. American Insurance Co. v. Canter, 1 Pet. 511; Benner et al. v. Porter, 9 How. 235; Clinton v. Englebrecht, 13 Wall. 434. They are courts of the Territories, invested for some purposes with the powers of the courts of the United States. Writs of error and appeals lie from them to the Supreme Court of the Territory, and from that court as a territorial court to this in some cases.

Sect. 808 was not designed to regulate the impanelling of grand juries in all courts where offenders against the laws of the United States could be tried, but only in the circuit and district courts. This leaves the territorial courts free to act in obedience to the requirements of the territorial laws in force for the time being. Clinton v. Englebrecht, supra; Hornbuckle v. Toombs, 18 Wall. 648. As Congress may at any time assume control of the matter, there is but little danger to be anticipated from improvident territorial legislation in this particular. We are therefore of the opinion that the court below no more erred in sustaining this indictment than it did at a former term, at the instance of this same plaintiff in error, in adjudging another bad which was found against him for the same offence by a grand jury composed of twenty-three persons. 1 Utah, 226.