Where the question of the authority of the agent is directly involved, it can only be proved by bringing evidence of the source of the agency, the act alleged constituting the principal's appointment and evidence of the agent's own statements or admissions, are not admissable against the principal for the purpose of proving the agency or extending the authority of the agent.20 Where the authority is in writing, the writing is the best evidence; the agent could not attempt to enlarge his powers by declarations contrary to the writing. But once the agency having been established by proper evidence as by the writing, or by witnesses to the appointment, then the statements of the agent may be shown and the whole matter may then all be considered of, by the jury. Whatever evidence tends to prove the fact of appointment, is ordinarily admissible, except in the given cases where a written or formal appointment must have been had, and if the appointment is lost, it must be accounted for. Where the facts are undisputed, the courts must determine whether the facts show that an agency has been created, and the extent of the same, where the facts are in dispute it is a question for the jury, who are judges of the fact.

The scope of the agent's authority may be shown by circumstances, as well as by proof of express authority, as authority expressly given includes whatever is fairly implied.21

18 Livnigs vs. Wiler, 32 I11., 387. 19 Smith on Merc. Law, 66 Id.,

Ch. 5. 20 Maxey vs. Heckethorn, 44 I11.,

438; Stollwerck vs. Thatcher, 115 Mass., 224, 66 I11. App., 293.

Where the whole authority does not grow out of written appointment, but where there is a subsequent broadening of the original authority, or the authority is extended, the rule is that this could be shown by parol testimoney.22

Where the agents authority rests in parol, he may be called as a witness if this is necessary and may testify as to the nature and extent of his authority.23 The principal may show also by his agent that the alleged authority has not been conferred.24 Authority includes with it, all the various means which are justified or allowed by the usages of trade.

21 Springfield Engine & Threshing

Co. vs. Green, 25 I11. App., 106.

22 Hartford Fire Ins. Co. vs. Wilcox,

57 Ili., 180. 23 Thayer vs. Meeker. 86 I11., 470. 24 Dowell vs. Williams,33 Kan.,319.