Such corporation may elect annually one of its own members to be president. He shall keep the minutes and enter the orders, acts and proceedings of the corporation in a book kept for that purpose, and shall have custody of the common seal and the papers, deeds, writings, documents and books of or relating to such corporation. He shall convene the corporation as occasion may require. In case of his absence for any cause, the office of president shall devolve on the senior trustee for the time being, who shall occupy the same until the return of the president or the election of another.