equitable right has once been created it may in its turn become the subject of a new equitable right, i.e., its owner may incur an equitable obligation to hold his equitable right for the benefit of some other person; and this process may go on ad infinitum, each new equitable right becoming in its turn the subject of still another equitable right, and all the equitable rights being derived from the same legal right, the first immediately, the others mediately. It is to be observed that these equitable rights are created without any alienation or diminution of the rights from which they are derived. For it is not the nature of an obligation, real or personal, legal or equitable, while it remains an obligation merely (that is, while it remains unperformed) to alienate or diminish in any way any right vested in the obligor. In the case, therefore, of a succession of equitable rights derived from one legal right, the legal right remains undiminished in its original owner, and so does each equitable right, and yet the equitable rights add nothing to the sum of human rights,[1] the aggregate of the legal right and all the equitable rights only equalling the legal right. So if the legal right be destroyed (e.g., by the act of God), all the equitable rights will fall to the ground. It is to be further observed that the legal owner is bound only to the original equitable owner, and the latter to the second equitable owner, and so on. If the legal owner and the equitable owners be conceived of as standing in a line, one behind the other, in the reverse order of the time of the creation of their rights, it will be seen that each one in the line is equitably bound to the one immediately before him, and to no one else, and hence that there are as many equitable bonds as there are persons in the line, less one,—the one standing in front being, of course, subject to no bond.
The foregoing method of deriving an indefinite succession of equitable rights from one legal right may be termed the method by sub-obligation.
Another method is for the first equitable obligee to assign his equitable right, at the same time receiving from the assignee a new equitable obligation. He may then assign his new equitable right to a new assignee, at the same time receiving from the latter still another equitable obligation; and this operation may be repeated indefinitely. This method takes place in the common case where
