THE AGENT'S AUTHORITY SUM MARIZED. The agent's authority in dealing with third persons comprises a number of elements which are thus summarized by Professor Mechem: i. It consists of the powers directly and intentionally conferred by the voluntary act of the principal. 2. Of those incidental powers which are reasonably neces sary and proper to carry into effect the main powers conferred and which are not known to be prohibited. 3. Of those powers which usage and custom have added to the main powers, and which the parties are to be deemed to have had in contemplation at the time of the creation of the agency, and which are not known to have been forbidden. 4. Of all such other powers as the principal has, by his direct act or by negligent omis sion or acquiescence, caused or permitted persons deal ing with the agent reasonably to believe that the prin cipal had conferred. 5. Of all those other powers whose exercise by the agent, the principal has subsequently, with full knowledge of the facts, ratified and confirmed. (Agency, Sec. 282.) The same elements apply as be tween principal and agent, save that the secret limita tions of power given the agent, are binding on the lat ter (idem).