The appointment of the agent may be made orally 4 or by an informal writing5 or under a formal power under seal.6 Most appointments are informal. In the commercial world, the actual authority conferred is oftentimes by a mere word, or sign, to the agent, and good faith requires the principal to stand by such a manner of an appointment, where to deny it would bring injury to an innocent party who, relying on such an appointment, dealt with the agent, as such.

The principle of estoppel, would be applied against one and bind him as a principal, where he stands by and permits a third person to deal with one, who makes a contract with the third person, for him as agent.7