For the efficient administration of the functions vested in the registrar by this chapter, he may require, by subpoena issued by him or under his direction, (1) the attendance of any witness and the production of any book, paper, document, or other evidence from any place in China at any designated place of hearing in China, or, if the witness is actually resident or temporarily sojourning outside of China, at any designated place of hearing within fifty miles of the actual residence or place of sojourn of such witness, and (2) the taking of a deposition before any designated person having power to administer oaths. In the case of a deposition, the testimony shall be reduced to writing by the person taking the deposition or under his direction, and shall then be subscribed by the deponent. The registrar, or any officer, employee, or agent of the United States authorized in writing by him, may administer oaths and examine any witness. Any witness summoned or whose deposition is taken under this section shall be paid the same fees and mileage as are paid witnesses in the courts of the United States.