The defendants attempt to justify the acts complained of, under the authority conferred upon the city council, by the ninth section of the city charter, “ to cause drains and common sewers to be laid down through streets and private lands.” But this is insufficient. All the land of which the plaintiffs appear to be in possession was acquired by them under and by virtue of the provisions of their act of incorporation, and solely for the accomplishment of the object contemplated in its enactment. It was thus, in the exercise of the right of eminent domain, and under a special statute expressly authorizing and allowing it, appropriated to the public use. For this purpose only the plaintiffs were constituted a corporation, with the privilege of establishing, constructing and maintaining a navigable canal, which should constitute a common and public way, open to all persons disposed, upon the terms prescribed by .aw, to avail themselves of the means afforded by it for travel or the transportation of their property. And having accepted the grant and constructed their canal, they are expressly required *226and bound to keep* it constantly in a safe and navigable state of repair ; so that the facilities which it is capable of affording, and the advantages which may be derived from its use while in such condition, may be uninterruptedly enjoyed by the community. S¿. 1792, c. 13, § 10. Being subject to this responsibility, it is obvious that anything which tends to obstruct, or to create an impediment in the navigation of their canal, must necessarily bring upon them increased charges and expenditures. If such effects are produced by the unlawful acts and interference of other parties, the plaintiffs will have good cause of action against the wrongdoers to recover compensation for whatever damages or injury they may have thereby sustained.

It is undoubtedly true that land or other property, which has once, in conformity with the provisions of the Constitution, been devoted to the public use, may afterwards in like manner be again taken and appropriated to the public service under a subsequent statute duly enacted, if such a purpose is expressly, or by unavoidable implication, authorized' by its provisions. For, in every exigency that can from time to time occur, the right to take private property for public use must remain paramount in the State, or its power to promote the general welfare would be paralyzed and destroyed. It belongs to the legislature to determine when these exigencies arise, and upon what occasions this extreme right of the government shall be exercised and enforced. Thus, a portion of land laid out for a public common, may by special provision of law be converted into a public highway; and again, a portion or the whole of a public highway may be appropriated to the service of a private corporation empowered to construct, and required to maintain for the public use an iron railway. Wellington, petitioners, 16 Pick. 103. Springfield v. Connecticut River Railroad, 4 Cush. 72. These cases afford illustrations of the general power of the legislature to devote to another and new service, for the use and accommodation of the public, any species of private property, although it may have before, for a similar purpose but in a different manner, been specially set apart and appropriated.

But if such an appropriation has once been made, the prop*227erty cannot afterwards be interfered with, or the right of holding and enjoying it in that definite manner be interrupted or disturbed, except under the provisions of some subsequent statute, expressly or by necessary implication authorizing its subjection to public service in another and different manner. This principle, applied to the present case, is decisive of the rights of the parties in relation to the point in controversy between them. The plaintiffs have, under their charter, already acquired the exclusive right to the possession and occupation of the lands upon and through which the defendants have caused their drains to be laid and constructed.

But the defendants contend that this right has been superseded by the same authority from which the grant of it was derived. This undoubtedly could have been done. For it is, as has already been shown, clearly competent for the legislature, in order to meet a pressing emergency and to accomplish some object of immediate public necessity or importance, to determine that a new appropriation of these lands ought to be allowed. If it should be found essential or reasonably necessary for the public good, as, for instance, to preserve or promote the health of the inhabitants of a city rapidly increasing in population, to take the lands and use the canal of the plaintiffs for the purpose of drainage, such an appropriation might undoubtedly be made under statutes containing suitable provisions and conferring the requisite authority. But no such necessity is declared, nor is any such right given to the defendants by any of the provisions of their city charter. The city council are indeed therein allowed, by a provision expressed in very general terms, to lay down drains and sewers through streets and private lands. But in this there is no such directness and particularity as to import that a new appropriation to the public use of land which had already been lawfully taken, and was still held and devoted by the plaintiffs to another public service, was intended by, or even at all in the contemplation of, the legislature. Indeed, we think it sufficiently appears from the phraseology of the act, that nothing of that kind was intended; for the right granted to the city, in relation to the location and construction of drains, extends only to a privilege *228of entering upon and occupying “ streets and private lands.” Without giving to these words a forced meaning, much enlarged beyond their just and proper signification, they cannot be considered as descriptive of, or designed to comprehend, the plaintiffs’ canal. At any rate, no express authority is conferred upon the defendants, either to occupy or interfere with the lands of the plaintiffs, so as to disturb them in the enjoyment of their franchise ; nor is there anything in the statement of facts upon which the case is submitted, which will warrant the conclusion that in the exercise of the authority conferred on the defendants there is any actual or substantial necessity for occupying any part of the plaintiffs’ property.

It has been suggested, in the argument for the defendants, that the right of the plaintiffs to the lands taken by them for the purpose of locating and establishing their canal, which might have otherwise been absolute and conclusive, is modified and limited by the fact that the canal was constructed, in fact, in and along the channel of an ancient brook flowing through the territory of which the city of Lowell consists. But this can make no difference. Whatever was the condition or use of the land or property at the time it was taken by the plaintiffs, as it was then lawfully taken and appropriated by virtue of their chartér to the public use, they have still the right to hold and retain it exclusively in their own possession, according to the terms of their grant. This is a right to an unmolested enjoyment of the property ; and it is just as clear and unqualified in relation to the stream referred to, including its banks and channel, as to any of the lands through which the canal was excavated or constructed.

Pursuant to the agreement of the parties this action is to stand for trial, solely for assessment of damages sustained by the plait* tiffs by the acts complained of