At Council meetings, the Mayor shall decide questions of order and may, without vacating the chair, give his reasons for his decision.  From any decision of the chair, an appeal may be made to the body in session, the question being “Shall the decision of the chair be sustained?” Upon such appeal no debate shall be allowed if it refers to a question of decorum, but if it relates to the priority of business or to the relevancy or applicability of propositions, the appeal may be debated.