It is conceded in the argument of the plaintiff’s counsel, that, the mill-wheels, for the value of which this action was brought, must be considered, as between mortgagor and mortgagee, fixtures belonging to the realty. They were essential to the operation of the mill, and were intended, when completed an4 paid for, to be permanently attached to the land. If the mortgagor had himself annexed them to the freehold, there could be no doubt that the mortgagee would hold them under his mortgage, and that they could not be severed without his consent. Winslow v. Merchants' Ins. Co. 4 Met. 306. But it is contended that the mortgagor being in possession, and having agreed with Burghardt that the wheels should remain the personal property of the builder until they were completed and provision made for paying fox them, the wheels, having *525been set up under this agreement, could not be claimed and held by the mortgagee.
If this position were tenable, it would follow that the mortgagor could convey to another a right in the mortgaged premises greater than he could exercise himself. But it is well settled that, although the mortgagor, for some purposes, and as to all persons except the mortgagee, may be regarded as the absolute owner of the land, yet the title of the mortgagee is in all respects to be treated as paramount. The mortgagor cannot make a lease which will be valid against the mortgagee; and if the mortgagee enter, neither the mortgagor nor his lessee will be entitled to emblements. Pow. Mortg. c. 7. Keech v. Hall, 1 Doug. 21. Lane v. King, 8 Wend. 584. Mayo v. Fletcher, 14 Pick. 525. And we think it is not in the power of the mortgagor, by any agreement made with a third person after the execution of the mortgage, to give to such person the right to hold anything to be attached to the freehold, which as between mortgagor and mortgagee would become a part of the realty. The entry of the mortgagee would entitle him to the full en joyment of the premises, with all the additions and improvements made by the mortgagor or by his authority.
Whether a person putting a building upon land by license of the mortgagor, under such circumstances that it would remain his personal property as against the mortgagor, would be allowed in equity to maintain a bill to redeem, if the mortgagee should enter, is a question involving very different considerations. A tenant mder a lease may redeem, to protect his interest. Rev. Sts. c 107, § 13. Bacon v. Bowdoin, 22 Pick. 401.
It has been suggested that the defendants cannot avail themselves of their title as mortgagees, because they acquired the title of the' mortgagor also, and therefore the mortgages are to be regarded as paid or merged. But it has been often decided that the purchaser of an equity of redemption may take an assignment of the mortgage, and may keep the legal and equitable titles distinct, at his election, if he has any interest in so doing, so that they shall not merge by unity of possession. And a release of an equity of redemption operates as an ex-*526tinguishmént of the equity of redemption, and not as a merger of the estate conveyed by the mortgage. Loud v. Lane, 8 Met. 517. Exceptions overruled.