Where defendant agreed to pay a broker $500 if he sold a lease for $1,500, and the broker produced a purchaser who paid $1,500 for an assignment, but was unable to comply with the further agreement, to make a deposit to secure the rent, so that the lease was not transferred, the broker was entitled to commissions. Swank v. Roberts, 124 P. 104, 24 Cal. App. 730.