Morton, J.

The rights of the parties in this case are determined by the rules as to fixtures which apply in cases between mortgagor and mortgagee.

*545The boiler, which the plaintiff contends was annexed to and became a part of the realty, was placed in the building, which was a machine-shop, by Stevens, the mortgagor, for the purpose of furnishing the motive power for the machinery. It was firmly attached to the land, was, in connection with the steam-engine, shafting and machinery, adapted to said machine-shop and business, and was essential to the enjoyment and use of the building, for the purpose for which it was intended. It therefore became a part of the realty,' and passed to the plaintiff by its mortgage. McLaughlin v. Nash, 14 Allen, 136. Pierce v. George, 108 Mass. 78. McConnell v. Blood, 123 Mass. 47.

The fact that the sections of the boilers could be removed without disturbing the brick-work, by which it was supported and encased, is immaterial. The boiler as a whole had become a part of the realty. As stated in McConnell v. Blood, ubi supra, whatever is placed in a building by the mortgagor to carry out the obvious purpose for which it was erected, or to permanently increase its value for occupation, becomes part of the realty, though not so fastened that it cannot be removed without serious injury either to itself or to the building.

The defendant contends that the boiler did not become a fixture, because it was delivered to Stevens to be used on trial, with the agreement that it should remain the personal property of the defendant until it was paid for. Such agreement would prevent Stevens from claiming it as a part of the realty; it would also prevent any vendee or mortgagee who took with notice of the agreement.

But where, as in this case, personal property is sold for the purpose of being annexed to the realty, and it is so annexed, an agreement between the seller and the buyer that it shall not become a part of the realty, but shall remain the personal property of the seller, will not bind or affect a vendee or mortgagee without notice. Notwithstanding such agreement, the property will pass to such vendee or mortgagee as a part of the realty. Hunt v. Bay State Iron Co. 97 Mass. 279. Thompson v. Vinton, 121 Mass. 139. As it is found as a fact in this case that the plaintiff had no notice of the agreement between the defendant and Stevens until after the mortgage deed was de*546livered, it follows that its rights are not affected by that agreement.

For these reasons, we are of opinion that the justice who presided at the hearing was justified in his finding that the boiler became a part of the real estate and passed by the mortgage from Stevens to the plaintiff. Exceptions overruled