By the indenture between the plaintiffs and the defendants, either party was authorized to build a party wall of brick with stone foundation, half on the land of each, and half the cost of which should be paid by the other if he used it. The defendants made a contract with a firm of masons, by which the latter were to furnish all the materials and labor in completing the stone and brick work, lathing and plastering, according to the plans and specifications and under the superintendence and to the acceptance of an architect, who was called in this contract and was in fact the agent of the defendants. The masons built the party wall, ninety feet long and fifty feet high, and did everything that they were required by their contract to do to it; the architect surveyed and estimated the work, and gave them a certificate therefor, which, by the contract, entitled them to receive three fourths of the amount already due them, under the contract, for labor and materials; and carpenters employed by the defendants put in the timbers of the floors and some of those required to support the roof. After the wall had been so com pleted by the masons and accepted by the defendants, it fell, and crushed the building and property upon the adjoining lot of the plaintiff's.
*238There was evidence tending to show that the fall of the wall was occasioned by negligence in building it without sufficient stays or supports, or in building it in such cold weather that the mortar froze as soon as laid and was afterwards softened by a sudden thaw. The jury were instructed that if the accident was caused by such negligence, the defendants would be liable, although it was the negligence of the masons in executing their contract. We are of opinion that this instruction was sufficiently favorable to the defendants.
The general rule of law, stated by Mr. Justice Blackburn in delivering the unanimous judgment of the Court of Exchequer Chamber, in Fletcher v. Rylands, L. R. 1 Ex. 265, 279, affirmed by Lord Cairns and Lord Cranworth in the House of Lords in the same case, L. R. 3 H. L. 330, 839, 340, and approved by this court in Shipley v. Fifty Associates, 106 Mass. 194, 198, is that “ the person, who for his own purposes brings on his lands and collects and keeps there anything likely to do mischief if it escapes, must keep it in at his peril; and, if he does not do so, is primd facie answerable for all the damage which is the natural consequence of its escape.”
This rule has been applied to dangerous animals; 1 Hale P. C. 430; Cox v. Burbridge, 13 C. B. (M. S.) 430; to cesspools; Tenant v. Goldwin, 1 Salk. 21, 360; S. C. 2 Ld. Raym. 1089, and 6 Mod. 311; Ball v. Nye, 99 Mass. 582; to artificial reservoirs of water; Fletchers v. Rylands, above cited; Gray v. Harris, 107 Mass. 492 ; and to accumulations of snow and ice upon a building by reason of the form of its roof; Shipley v. Fifty Associates, above cited.
The only exceptions to the liability, which have been judicially recognized, are in case of the plaintiff’s own fault, or of vis major, the act of God, or the acts of third persons, which the owner had no reason to anticipate. Fletcher v. Rylands, L. R. 1 Ex. 280, and L. R. 3 H. L. 340. Nichols v. Marsland, L. R. 10 Ex. 255, and 2 Ex. D. 1. Humphries v. Cousins, 2 C. P. D. 239. Mahoney v. Libbey, 123 Mass. 20. In Fletcher v. Rylands, it was found, in the case stated, that “ for the selection of the site, and for the planning and construction of the reservoir, it was necessary that the defendants should employ an engineer and contractors ; and they did for those purposes employ a com*239petent engineer and competent contractors, by whom the site was selected, and the reservoir planned and constructed; on the part of the defendants themselves, there was no personal negligence or default whatever; but reasonable and proper care and skill were not exercised by the persons they employed, to provide for the sufficiency of the reservoir to bear the pressure of water which, when filled to the height proposed, it would have to bear.” And it was unavailingly argued by Mr. (afterwards Lord Justice) Mellish, that the defendants were not liable for the negligence of contractors employed by them. L. E. 1 Ex. 268, 269, 276.
An owner of land has the same duty to keep on his own land a house or wall built thereon, as the filth in his cesspool, or the water in his reservoir, or the snow and ice upon his roof. His duty is, in the words of Baron Parke, “ to keep it in such a state that his neighbor may not be injured by its fall.” Chauntler v. Robinson, 4 Exch. 163, 170.
In Nichols v. Marsland, Baron Bramwell said: “ What is the difference between a reservoir and a stack of chimneys for such a question as this ? Here the defendant stored a lot of water for her own purposes; in the case of the chimneys some one has put a ton of bricks fifty feet high for his own purposes; both equally harmless if they stay where placed, and equally mischievous if they do not.” “ I admit that it is not a question of negligence. A man may use all care to keep the water in, or the stack of chimneys standing, but would be liable if through any defect, though latent, the water escaped or the bricks fell.” L. E. 10 Ex. 259, 260. See also Tarry v. Ashton, 1 Q. B. D. 314; Bower v. Peate, 1 Q. B. D. 321; Gray v. Boston Gas Light Co. 114 Mass. 149.
The present case does not require us to decide whether it is more accurate to say that it is not a question of negligence and that the defendant is liable even in case of latent defect; or to say that the fall of the wall, in the absence of proof of inevitable accident or of the wrongful act of third persons, is sufficient evidence of negligence. See Ball v. Nye, and Shipley v. Fifty Associates, above cited; Kearney v. London & Brighton Railway, L. R. 5 Q. B. 411, and L. E. 6 Q. B. 759; Mullen v. St. John, 57 N. Y. 567. As was well observed by Mr. Justice Lush, in *240Tarry v. Ashton, negligence is a relative term, depending upon the question, What is the duty of the defendant? 1 Q. B. D. 318. In the case at bar, the jury, under the instructions given, must have found negligence, either in the defendants themselves or in the masons employed by them to build the wall.
Assuming that the relation of the masons to the defendants was that of contractors, the former alone would be responsible to a third person for any injury caused by their negligence in a matter collateral to the contract, as, for instance, in depositing materials, handling tools, or constructing temporary safeguards, while doing the work; but where the very thing contracted to be done is improperly done, and causes the mischief upon the land of another, the employer is responsible for it, at least when it occurs after the structure has been completed to his acceptance. Fletcher v. Rylands, above cited. Hole v. Sittingbourne & Sheerness Railway, 6 H. & N. 488, 500. Butler v. Hunter, 7 H. & N. 826, 833. Hilliard v. Richardson, 3 Gray, 349, 353. Chicago v. Robbins, 2 Black, 418, 428. Conners v. Hennessey, 112 Mass. 96. Boswell v. Laird, 8 Cal. 469, 498.
The whole wall, when completed and accepted, was, by virtue of the indenture between the defendants and the plaintiffs, owned by the defendants until they should be reimbursed half the cost of it by the plaintiffs. Richardson v. Tobey, 121 Mass. 157. For the injury caused to property on the adjoining land by the falling of this wall, by reason of its defective and unsafe condition, whether owing to their own negligence or to that of the masons who had built it, the defendants are responsible.
The evidence objected to was rightly admitted. The indenture between the parties, in referring to “ the custom in regard to party walls in the city of Worcester,” evidently had in view not a technical custom, but the usual practice, like the previous clause in the same paragraph, which speaks of the ways and purposes in and for which “ party walls are usually constructed.”
Exceptions overruled,