Agency coupled with interest: A gives authority to B to sell A’s land, and to pay himself, out of the proceeds (to the debt due to him from A) . A cannot revoke this authority, nor can it be terminated by his insanity or death.
By act of parties: By agreement; By revocation and renunciation; By completion of performance.
By operation of law: By death or insanity; By insolvency of the principal.
Other modes of termination: By efflux of time (fixed period); By destruction of the subject-matter; By incapacity of Principal or Agent; Principal and Agent becoming alien enemy; By object of Agent becoming unlawful.