Error in the instruction on a contract to procure a purchaser for defendant's land, wherein plaintiff contended that he found purchasers and that the sale failed solely because of defendant's defective title, in that the instruction was open to a construction that, from the fact that the attorney for the purchasers saw the deed, it was conclusively established that the purchasers knew the reservation therein of marl mineral and gas deposits, was not cured by undisputed testimony that plaintiff stated to the purchasers, or one of them, that defendant would reserve the mineral deposits, or by the further instruction that plaintiff must prove that the purchasers knew about and consented to the reservation. Weaver v. Richards, 150 Mich. 20, 113 N. W. 867, 14 D. L. N. 617, 120 N. W. 818, 16 D. L. N. 117.