In an action to recover commissions for a sale of real estate, plaintiff alleged a contract whereby defendant agreed to pay him a certain sum if he would find a purchaser for his property, and that he did so; defendant alleged that plaintiff had not the exclusive right to dispose of the property under the agreement, and that defendant had sold it himself. Held, to present a question of fact for the jury. Black v. Snook, 204 Pa. St. 119, 53 A, 648; Bothenburger v. Schoningerg, 30 Ky. L. E. 1018, 99 S. W. 1150; Cesana v. Johnson, 122 N. E. 444, - Mass. Sup. -; Harris v. Millikan, 208 S. W. 633, - Mo. App. - . Where the authority is conferred on the agent by a written instrument its construction is for the court. Grosscup v. Downey, 105 Md. 273, 65 A. 930