The authority of the legislature to empower persons or corporations to erect and maintain bridges over navigable waters within the limits of the Commonwealth, and thereby to obstruct in a greater or less degree the free passage of vessels and boats over and through the same, is clear and unquestionable. Commonwealth v. Breed, 4 Pick. 460. Commonwealth v. Proprietors of New Bedford Bridge, 2 Gray, 339, and cases cited. Nor can we entertain any doubt that, by the fair import of the terms of St. 1851, c. 338, § 1, under which the defendants built the structure which constitutes the obstruction and nuisance set out in the indictment, they were authorized to erect it without a draw for the passage of vessels. Not only is there no express requirement in the act that a draw shall be built, such as is always inserted in enactments authorizing the construction of a bridge over navigable waters when the legislature intend to secure a free passage for vessels, but there is in effect a permission given to the defendants to build the bridge continuously over the river, and at a certain height or distance above the surface of the water in the two channels. The purpose of such a permission is manifest. It is to secure a fixed and permanent space between the under part of the bridge and the water in the channel, for the more convenient passage of boats, scows, and rafts, which would be wholly unnecessary and useless if an open draw was intended to be prescribed as a part of the erection authorized by the statute. This interpretation of the act acquires additional strength from the fact that all previous bridges erected at the same place over the river from the year 1760 to the year 1851, when the statute above cited was passed, were built without draws. The main purpose of the last named act was to authorize the defendants “ to alter, enlarge and reconstruct” the bridge then existing over the river. The particulars in which the alteration and enlargement were to be made in the reconstruction were specified in the statute, but no provision is inserted requiring it *312to be rebuilt with a draw. This omission is significant to show that the legislature did not intend to impose such a burden on the defendants.
It follows that the defendants, having built their bridge in conformity to the authority conferred on them by law, have caused no unláwful obstruction of the river, and are not guilty of the nuisance charged in the indictment.
Verdict set aside.