[1] Agency — Revocation op Authority — Power op Principal.— A principal has the power to revoke an agent’s authority at any time before the agent has completed performance, save in the case of an agency coupled with an interest.

[2] Id.—Limitation upon Right op Revocation—Contract op Principal.—A principal may curtail his right of revocation of an agent’s authority by contracting not to revoke the authority for a definite time.

[3] Id.—Revocation Within Limited PIeriod—Right op Principal— Liability to Agent.—A principal who contracts not to revoke the authority of an agent for a definite time still retains the power to terminate the agency within the designated period, but if he does so, he renders himself liable for damages for the violation of a legal right of the agent.

[4] Brokers — Negotiation op Exchange — Irrevocable Opper por Ten Days — Revocation op Agency — Right op Principal.— Under a contract between an owner of real property and a firm of real estate agents containing an offer to exchange such property for that of a third person and providing that the offer' should be null and void unless accepted within ten days, but that during such period the offer should be irrevocable, and further providing that such agents should act as the agent in negotiating the exchange, the owner had the right to revoke the agent’s authority at will, since the contract contained no provision that the agency should continue for any specific period, and the ten days allowed for acceptance was a part of the offer.

4. Revocation of authority of real estate broker, notes, 2 Ann. Cas. 886; 12 Ann. Cas. 1085; Ann. Cas. 1918D, 339.

[5] Contract —• Irrevocable Offer — Lack of Consideration—Right of Revocation.—An offer to exchange real property providing that the offer shall he irrevocable for ten days is revocable at any time before acceptance, where the offer and the agreement not to revoke are made without consideration.

[6] Brokers—Action for Services—Evidence—Questions by Court —Disclosure of Material Facts of Defense—Lagk of Prejudice.—In an action for broker’s services in procuring an alleged acceptance of an offer of exchange, questions put by the court to plaintiff, while appearing as a witness in his own behalf, resulting in the disclosure, upon his case in chief, of facts material to the defense, were not prejudicial, where no harm appears to have resulted and plaintiff’s counsel was given ample opportunity to examine the witness after he had answered the questions.

[7] Evidence—Examination of Witnesses—Power of Court.—It is within the power of the court to call or examine witnesses in furtherance of justice against the will of either- party.

[8] Brokers-—Defense of Specific Performance Action—Nonliability for Expenses of Principal.—A broker authorized to negotiate an exchange of real property is not liable to his principal for the expenses incurred by the latter in defending the other exchanging party’s action for specific performance, on the theory that the broker violated instructions in procuring acceptance of the offer after revocation, where the ‘other exchanging party had knowledge of such revocation and notwithstanding claimed the right to accept under the provision of the contract providing that the offer should be irrevocable for ten days.