An instruction requested by plaintiffs, in an action by real estate agents for commissions, that, though the jury find it was agreed between plaintiffs and defendants that commissions should not be paid unless defendants actually traded a certain building for a ranch controlled by plaintiffs and passed title, yet if they find that it was the act of defendants which prevented the exchange being made, they should find for plaintiffs, they having procured a person ready and able to make such trade on terms satisfactory to defendants, is properly refused as misleading, it being conceded that, as between defendants and the owners of the ranch, it was the act of defendants which prevented the exchange being made, and there being evidence that the act was compelled against the wishes of defendants by circumstances which they could not avoid, and which, under the contract of employment was sufficient to absolve them from liability for the commissions. Rieger v. Merrill, 125 Mo. App. 541, 102 S. W. 1072. See also Sec. 125.