(1) The liability of a principal debtor and that of his surety, provided that the contract of suretyship is subsequent to, or otherwise independent of the creation of the debt so guaranteed. But if the two debts have the same origin, as where the principal debtor and the surety sign a joint bond, the case is one of joint obligation.
(2) The liability of two or more co-sureties who guarantee the same debt independently of each other.[[456]] They may make themselves joint, or joint and several debtors, on the other hand, by joining in a single contract of guarantee.
(3) Separate judgments obtained in distinct actions against two or more persons liable for the same debt. Two persons, for example, jointly and severally liable on the same contract may be separately sued, and judgment may be obtained against each of them. In such a case they are no longer jointly liable at all; each is now severally liable for the amount of his own judgment; but these two obligations are solidary, inasmuch as the satisfaction of one will discharge the other.
(4) The liability of independent wrongdoers whose acts cause the same damage. This is a somewhat rare case, but is perfectly possible. Two persons are not joint wrongdoers, simply because they both act wrongfully and their acts unite to cause a single mischievous result. They must have committed a joint act; that is to say, they must have acted together with some common purpose. If not, they may be liable in solidum and severally for the common harm to which their separate acts contribute; but they are not liable as joint wrongdoers. In Thompson v. The London County Council[[457]] the plaintiff’s house was injured by the subsidence of its foundations, this subsidence resulting from excavations negligently made by A., taken in conjunction with the negligence of B., a water company, in leaving a water-main insufficiently stopped. It was held that A. and B., inasmuch as their acts were quite independent of each other, were not joint wrongdoers, and could not be joined in the same action. It was said by Lord Justice Collins:[[458]] “The damage is one, but the causes of action which have led to that damage are two, committed by two distinct personalities.” The liability of the parties was solidary, but not joint.[[459]] So also successive acts of wrongful conversion may be committed by two or more persons in respect of the same chattel. Each is liable in the action of trover to the owner of the chattel for its full value. But they are liable severally, and not jointly. The owner may sue each of them in different actions; though payment of the value by any one of them will discharge the others.[[460]]
Examples of joint obligations are the debts of partners, and all other solidary obligations ex contractu which have not been expressly made joint and several by the agreement of the parties.
Examples of joint and several obligations are the liabilities of those who jointly commit a tort or breach of trust, and also all contractual obligations which are expressly made joint and several by the agreement of the parties.
§ 167. The Sources of Obligations.
Classed in respect of their sources or modes of origin, the obligations recognised by English law are divisible into the following four classes:
(1) Contractual—Obligationes ex contractu. (2) Delictal—Obligationes ex delicto. (3) Quasi-contractual—Obligationes quasi ex contractu. (4) Innominate.