In an action for the breach of an agreement to permit plaintiff to sell land on commission, where the number of acres in the tract was uncertain, the amount which plaintiff was entitled to recover depending on the number of acres, was for the jury, so that it was error to charge that plaintiff was entitled to recover a certain sum, if they found the contract as alleged. Jackson v. Stephenson (Tex. Civ. App. '08), 114 S. W. 848.