Where an agent has been employed to sell land at no fixed rate of compensation, the jury are to fix the value of his services in the premises from the work done; and in fixing the amount, the rate usually paid professional land brokers for such services may be taken into consideration. Ruckman v.

Berghoh, 38 N. J. L. 531; Burdon v. Briquilet, 125 Wis. 341, 104 N. W. 83. See also Sec. 513.