If an agent deals on his own account in the business of the agency, without first obtaining the consent of his principal and acquainting him with all material circumstances which have come to his own knowledge on the subject, the principal may repudiate the transaction, if the case shows, either that any material fact has been dishonestly concealed from him by the agent, or that the dealings of the agent have been disadvantageous to him.
Illustrations
(a) A directs B to sell A's estate. B buys the estate for himself in the name of C. A, on discovering that B has bought the estate for himself, may repudiate the sale, if he can show that B has dishonestly concealed any material fact, or that the sale has been disadvantageous to him.
(b) A directs B to sell A's estate B, on looking over the estate before selling it, finds a mine on the estate which is unknown to A. B informs A that he wishes to buy the estate for himself, but conceals the discovery of the mine. A allows B to buy, in ignorance of the existence of the mine. A, on discovering that B knew of the mine at the time he bought the estate, may either repudiate or adopt the sale at his option.