Although the broker finds a customer before the principal sells the property, he is not entitled to a commission if he delays to notify the owner until after a sale is made by the latter. Bears v. Hyland, 65 Minn. 150, 67 N. W. 1148; Barnett v. Gluting, 3 Ind. App. 415, 29 N. E. 154, 927; Burnett v. Ed-ling, 19 Tex. Civ. App. 711, 48 S. W. 775. See also Secs. 489, 558. Compare Sec. 871.