The authority of the principal's agent, in this case his father, to employ a broker is a question of fact that should have been submitted to the jury. Phillips v. Hazen, 122 Iowa, 475, 98 N. W. 305; Codd v. Seitz, 94 Mich. 191, 53 N. W. 1057; Groscup v. Downey, 105 Md. 273, 65 A. 930; Lanhart v. Bean, 161 N. W. 464, - Iowa Sup. - .