The authority may be considered as revoked by a failure to act upon it within a reasonable time, or by a failure to conform to the terms of the authority. It may be considered revoked by a refusal to act upon it and the proposal of other terms not accepted by the drawee,1 as well as by a statement of the person authorized to both drawee and payee that he would not act upon the authority.2 The authority when once acted upon to the extent of the power granted is exhausted,3 and the authority may be revoked whether the payee knows that fact or not.4 He takes the risk of the power being no longer in existence, just as he does when an authority is granted by a telegram, but another telegram has been sent revoking the authority, and he takes the draft in ignorance of the revocation.5 But a continuing authority exists until notice of revocation to the person authorized.6 The authority may be revoked at any time, as in the case of a permission to overdraw.7 But where the continuous authority has been addressed to a particular person to grant credit to the drawer, it would seem that in justice the revocation ought to be addressed to that person.