When the senate shall sit for the purpose of trying any impeachment, the speaker shall be sworn or affirmed by a member selected by the senate for that purpose by a majority of the members present. The speaker so qualified shall then administer the oath or affirmation to the members respectively, and the speaker of each house is hereby empowered to administer oaths or affirmations to witnesses or other persons whom it may be necessary to examine before the house whereof he is speaker; and the chairman of every committee shall have like powers in examinations before committees.
46 P.S. § 2