"Where, in an action by a broker for commissions for a sale of land, the petition declared on a verbal contract made on a certain day, and specifically set forth the terms of the agreement and its performance by plaintiff, an instruction that unless the jury believe that defendant expressly employed plaintiff on the day named as his agent to sell the land, they should find for defendant was proper. Fortran v. Stowers (Tex. Civ. App. '08), 113 S. W. 631. Compare Sec. 887.