Where a presumption of merger arises by reason of the union in the same person of a charge and of an estate of inheritance in the property charged, such presumption may be rebutted by a declaration that the charge shall be kept on foot for the benefit of his personal estate (k), or by clear expressions of such intention in the instrument which effects the union of the charge and the estate (I).

Even an express declaration against merger will not keep the charge alive if there are circumstances pointing conclusively to merger (m), but where there is such a declaration it is not necessary, as is sometimes done (n), to take a conveyance either of the charge or of the estate to a trustee so as to prevent a merger at law (o).

If, owing to a common mistake induced by the misconduct of the mortgagor, the deeds as framed do not express the true intention of the parties, they may be rectified under the equitable jurisdiction of the court so as to express such intention. Thus, land was subject to a first mortgage to A and to a second

(j) Crosbie-Hill v. Sayer, [1908] 1 Ch. 866, at p. 877; Fourth City Mutual Benefit Building Society v. Williams, 1879, 14 Ch.D. 140. Cf. Whiteley v: Delaney, [1914] A.C. 132, in Sec. 202, infra. As to the right of subrogation of a person who pays off a mortgage, see also chapter 8, The Registry Act, Sec. 78.

(k) Bailey v. Richardson, 1852, 9 Hare 734; Jameson v. Stein, 1855, 21 Beav. 5.

(l) Phillips v. Gutteridge, 1859, 4 DeG. & J. 531; In re Gibbon, Moore v. Gibbon, [1909] 1 Ch. 367.

(m) In re Gibbon, ubi supra, at p. 374.

(n) Bailey v. Richardson, ubi supra, at p. 736.

(o) This follows a fortiori from the cases which allow merger mortgage to M, and F agreed with L (a purchaser of the property), to advance money on the security of a first mortgage, for the purpose of paying off A's mortgage. The mortgagor did not disclose the existence of M 's mortgage and consequently the transaction was carried out in a form which would prima facie have the effect of extinguishing A's mortgage, namely by (1) a reconveyance by A to the mortgagor, (2) a conveyance by the mortgagor to L, (3) a mortgage by L to F, and delivery of the title deeds to F. In an action by M, who claimed that his mortgage had become the first mortgage, it was held that the plaintiff was not entitled to priority, on the following grounds, namely, (1) that the deeds could have been rectified in the action if the defendants had counterclaimed for that relief and that a court of equity would not in the circumstances enforce in favour of a volunteer (p) a title based upon deeds framed under a common mistake, (2) that F having acquired in equity the priority of A's mortgage by paying the mortgage debt and obtaining the title deeds, the plaintiff could not take advantage of the wrong of the mortgagor, through whom he claimed, to deprive F of that priority (q).