9. The commissioners or any of them may, by a summons under his or their hand or hands, require the attendance before them, at a place and time therein specified, of any person whose evidence may be material to the subject of inquiry, and may order any person to bring before them such books, papers, deeds and writings as appear necessary for arriving at the truth.
Every such person shall attend and answer all questions put to them by the commissioners touching the matter to be inquired into, and shall produce before the commissioners all books, papers, cheques, promissory notes, deeds and writings required of him and in his custody or control, according to the tenor of the summons.
The commissioners or any one of them may require the usual oath or affirmation from every person examined before them, and may administer the same.