If, however, appeal be made as in this Article provided for, the Supervisors, at the time and place specified in said notice, shall consider all the appeals, protests, grievances, claims and objections filed in the manner and within the time in this Article specified, and shall hear all evidence, statements and argument offered in support thereof. Such hearing may be postponed by said Supervisors from time to time, and all persons shall be deemed to have notice of all such postponements and shall be governed thereby.