British North America Act, 1867, S. 47
47. Until the Parliament of Canada otherwise provides, in case of the Absence for any Reason of the Speaker from the Chair of the House of Commons for a Period of Forty-eight consecutive Hours, the House may elect another of its Members to act as Speaker, and the Member so elected shall during the Continuance of such Absence of the Speaker have and execute all the Powers, Privileges, and Duties of Speaker.
Documents related to section 47
[Note: See also the provisions concerning the Speaker of the House of Commons in the Parliament of Canada Act (Canada).]