In an action by a broker to recover commissions for selling land, evidence that the act of the defendant prevented the happening of the contingency on which payment was to be made was inadmissible, the excuse not being pleaded by the plaintiff. Turner v. Lane, 93 N. Y. S. 1083, 47 Misc. 387. A broker may by special agreement with his principal so contract as to make his compensation depend upon a contingency which his efforts can not control, even though it relates to the acts of his principal. Hind v. Henry, 36 N. J. L. 328; Lassen v. Bayless, 125 Fed. 744, 60 C. C. A. 512; Berry v. Tweed, 93 Iowa, 296, 61 N. W. 858; Stewart v. Fowler, 37 Kan. 677, 15 P. 918; Flower v. Davidson, 44 Minn. 46, 46 N. W. 308; 8. E. Crowley Co. v. Myers, 69 N. J. L. 245, 55 A. 305; Brown v. Grossman, 65 N. Y. S. 1126, 53 App. Div. 640; Hodgkins v. Mead, 8 N. Y. S. 854. See also Secs. 40, 45, 65.

A written agreement, after reciting that defendant had contracted to sell a farm to one H, "contingent on the allowance of a certain pension to H," the latter's ability to pay the price being entirely dependent upon the allowance of said pension claim, provided that, in case the sale should be "perfected by the payment of said purchase money" to defendant, "in the event said pension is allowed," defendant should pay a specified commission to plaintiff, who had helped bring about the contingent sale, but if the "pension should not be allowed and paid over to defendant plaintiff should receive nothing; the price to be paid for the farm was $12,000 and the pension claim was for $9,500, of which H received $6,000, but never paid more than $1,000 to defendant. Held, that plaintiff was not entitled to a commission. Cobb v. Kenner (Ch. App. Tenn.), 42 S. W. 277.

The owner of certain real estate desiring to exchange the same for city property, on which were certain mortgages, employed plaintiffs, as brokers, to effect the exchange, requiring as a condition precedent that an extension of time for the payment of the mortgage be secured within ten days. Plaintiffs procured defendant, the owner of the city property, to endorse a written acceptance on the contract, and an agreement to pay $1,000 commission for the exchange, which was never consummated, because no extension of time for payment of the mortgages was obtained. Held, that it was plaintiffs' duty to procure such extension, in the absence of which he could not recover commissions. Henly, Halfhill & Nichlin v. Clagne, 120 P. 61, 17 Cal. App. 511.