“ Depositions of witnesses residing at any place may be taken upon stipulation of the parties, or by the mode provided in the rules of practice for the Courts of Equity of the United States, or as provided by sections 863, 865-867 of the Revised Statutes (28 USCA §§ 639, 641, 644, 645) for the taking of depositions de bene esse in the District Court, or as may be directed by the Master. They may be returned in the first instance to the Master. ”

“ The Special Master shall have authority (1) to employ competent stenographic and clerical assistants, (2) to fix the times and places of taking the evidence and to limit the time within which each party shall present its evidence, and (3) to issue subpoenas to secure the attendance of witnesses and to administer oaths. ”