A purchaser who paid money to a real estate agent employed by his vendor to induce the agent to assist him in the transaction is estopped to deny that the agent is his agent, when suit is subsequently brought by the vendor to reform the deed which was drawn by the agent for both parties, wherein a reservation of growing crops was by mistake omitted, since the mistake of the agent is the mistake of both principals. Warrick v. Smith, 137 I11. 504, 27 N. E. 709; Seymour v. Slide, etc., Gold Mines, 42 Fed. 633. See also Sec. 258.