*218 Peaslee, J.

If at the time Freeman caused the injury he was not acting within the scope of his employment, the defendant is not liable. Danforth v. Fisher, 75 N. H. 111. The evidence is conclusive to the effect that Freeman had no authority from the defendant to carry Wallace as a passenger. This excess of his authority continued as long as Freeman pursued the unauthorized course of conduct. He not only exceeded his authority in asking Wallace to ride, but also in receiving him into the car and in thereafter transporting him therein. In all that Freeman did touching the carriage of Wallace he acted outside the authority conferred upon him. From first to last it was his own undertaking and not that of the defendant.

But it- is said that, conceding this to be so, Freeman occupied a dual position. Personally, he was the host of Wallace, who rode as his guest, and as agent of the defendant he was engaged iñ driving the car from Boston to Manchester. Hence it is said, the defendant, through Freeman, knew of Wallace’s presence and was bound to act reasonably towards him in the operation of the car. The defect in this reasoning is that when the agent acts in this dual way knowledge on his part is not chargeable to his principal. Brookhouse v. Company, 73 N. H. 368. The application of the rule charging the principal with his agent’s knowledge “is limited by the reasons that sustain it.” Clark v. Marshall, 62 N. H. 498. Those reasons are wholly lacking in the present case.

- In driving the car to Manchester, Freeman was acting as the host of Wallace. Although driving the car also promoted the defendant’s business, such promotion bore no relation to the carriage of Wallace. The transportation of Wallace in no way aided the defendant’s work of taking the car to Manchester. It was not a reckless or careless method Freeman used to do his master’s work, but a distinct undertaking of his own. If the dual character of Freeman’s acts is to be considered at all it must be followed throughout the transaction. So far as he operated the car to carry Wallace, he did so as an individual. So far as Wallace was concerned it was Freeman, and not the defendant’s agent, who drove the car.

The law of agency rests upon the theory of a reasonable responsibility for acts of one’s servants. It is apparent that any theory which would result in making the defendant liable to Wallace for this accident, on the facts now appearing in evidence, would impose an unreasonable and unjust burden upon the employer.

The suggestion that Freeman had apparent authority to extend the invitation to Wallace, on behalf of the defendant, and that *219 Wallace acted on the strength of such appearances, is not borne out by apy evidence. There was nothing tending to show a custom of automobile dealers in general, or of this defendant, to so conduct the business. The evidence was that the defendant forbade such a proceeding, and there was no testimony tending to show that the situation was misunderstood by Wallace.

As there was no evidence to sustain a finding that Freeman was acting as the defendant’s agent in carrying Wallace, it is not necessary to consider many of the questions which have been argued. While it is true, as the plaintiff claims, that the extent of the authority conferred upon an agent may be a question of fact, yet the question whether there is any evidence to prove it is one of law. The plaintiff fails because he did not introduce evidence of the essential fact. If there had been testimony from which a finding of authority conferred could reasonably have been made, the case would have been for the jury; but it was error to permit them to find the fact without evidence.

The defendant’s motions should have been granted.

Verdict set aside: judgment far the defendant.

All concurred.