According to the fundamental rule in equity, What ought to be done, is considered as done,” when Moore ■executed and delivered his agreement of January 5, 1880, to W. A. Worster, therein promising to convey his interest in the property described, he thereby transmitted an equitable ■estate to Worster, who was then regarded as clothed with the .■same ultimate interest in the property which he would receive ¡and hold if Moore had actually fulfilled his agreement. Moore •then became the trustee of the estate for Worster, retaining ithe legal title as security for the purchase money, and Worster -the trustee of the purchase money for Moore. Linscott v. Buck, 33 Maine, 530; Green v. Smith, 1 Atk. 572; Broome v. Monck, 10 Ves. 597 ; Hadley v. Bank, 3 DeG. J. & S. 63 ; Pom. Eq. § § 368 et seq.; Rose v. Watson, 10 H. L. Cas. 672, 678; Lysaght v. Edwards, L. R. 2 Ch. Div. 499, 506. The estate of Worster, under this agreement, was of such a *295substantial character that he could sell, charge or encumber it by mortgage, as he did do to Mrs. Niles, before the conveyance from Moore. Seton v. Slade, 7 Ves. 265; Champion v. Brown, 6 Johns. Ch. 398, 403. And notice thereof to Moore would constitute him the trustee of Mrs. Niles. Story, Eq. § 789.

And the same principle would apply if the agreement, coupled with the anterior proceedings between Worster and the bank and Moore, be regarded as security for the payment of the balance of the six thousand one hundred and fifty dollar note, and therefore an equitable mortgage. For "equity regards the right of a mortgagor as the beneficial ownership of the land, subject, however, to the lion created by the mortgage as a security to the mortgagee for the payment of his demand. The mortgagor’s equitable property is, in this respect, exactly analogous to the equitable estate of a vendee subject to a lien in favor of the vendor, as security for the payment of the purchase price. ” Pom. Eq. § § 162, 163, 376. And while there are many facts and circumstances in this case tending to show that the negotiations by the bank, Moore and Worster, which resulted in the execution of the agreement of January 5, constituted a mortgage, still we have concluded to consider it as a conditional sale.

In his letter, Moore declined to release to any one claiming under Worster, on the ground that the agreement ran to Worster alone, and hot to him and his assigns. And when the tender was made in behalf of this complainant, he declined it. Moore’s counsel now contend that Worster had a right, in his own behalf, to demand and receive a conveyance on tender of the balance due under the agreement; but that if Moore had conveyed to the complainant, he would thereafter be liable to Worster. We do not so understand the rules in equity. To be sure in law, before our late statute, such an agreement could not be assigned so as to allow the assignee to bring an action thereon in his own name. But an assignment of a thing in action, though nugatory as a transfer at common law, is regarded in equity as clothing the assignee with all the rights of his assignor, and to be enforced at the suit of the assignee. Pom. *296Eq. § § 168, 369. And still, to hold Moore as the trustee of Worster’s assignee, notice to him was essential, in order that he might shape his course according thereto. For Moore had a substantial interest in the property, and a right to protect and assert it. And still he was bound to convey, not to Worster alone, but to whomsoever Worster might assign his interest, provided that assignee should seasonably pay or tender the sum due under the terms of the agreement. If instead of an executed mortgage or assignment, the negotiations between 'Worster and Mi’s. Niles had taken on the form of an agreement to assign, then notice of such an agreement would not have bound Moore to her, but he might, under that state of facts, convey to Worster, notwithstanding such an agreement. McCreight v. Foster, L. R. 5 Ch. 604, 610; S. C. sub nom. ; Shaw v. Foster, L. R. 5 H. L. 321, 333, 338, where Lords Chelmsford and Cairns elaborately discuss the subject.

In the case at bar, the notice given to Moore on January 3, was seasonable and ample, including copies of the mortgages and assignments, together with the dates of their respective registration.

So far as Moore is concerned,- we perceive no reason why he should not be decreed to release the unsold land described in his agreement to the complainant.

The defendant, Lyman, however, alleges that the mortgages of Worster to Niles are fraudulent as to him, as creditor of Worster; and that he, in December, 1880, in an action still pending, attached Worster’s right under the • agreement of January 5. There is no doubt that he had the right and authority to attach it. R. S., c. 81, § 56. But to avail himself of any such attachment, either he or Worster should have seasonably paid or tendered to Moore, the amount due under the agreement. If, as alleged, the mortgages to Niles are void, and the assignment of them to the complainant are, for the same reason, also void, then the tender to Moore was made by one having no right to the conveyance, and therefore of no avail, and the land has consequently been forfeited and the attachment has become valueless. We think, therefore, that Lyman can not set up that defence here.

*297Neither lias the bank any reason to defend. The money tendered belongs to the bank under Moore’s mortgage, which seems to have been purposely left unrecorded, until a long while after the registration of the Niles mortgages.

Whatever may be the rights of the parties, can be determined hereafter, the principal object being now to prevent a forfeiture of the land under the agreement of January 5.

Our opinion is that the bill should be sustained, that Moore, on the payment of the sum tendered January 3, should release to the complainant the unsold land described in his agreement of January 5, the complainant to hold the same in trust for the equitable owners of the property, in accordance with their respective priorities and claims to be hereafter determined.

Bill sustained with costs. Decree according to the opinion.