The authority of the attorney general, or other law officer empowered to represent the government, to file an information in equity to restrain and prevent a public nuisance seems to be well established in England. It may be done by him, either ex officio, or upon the relation of persons who have an interest in the subject matter of the bill and whose private rights may be protected by the decree which is sought mainly on the ground of a public injury. 1 Dan. Ch. Pract. 11. 3 Dan. Ch. Pract. 1858. 3 Story Eq. Jur. §§ 921, 926. Kerrison v. Sparrow, Coop. 305. Attorney General v. Johnson, 3 Wils. Ch. 87. Attorney General v. Forbes, 3 Myl. & Cr. 129, 133. Although in some of the earlier cases this jurisdiction was sparingly exercised, yet in recent practice it seems to have been more frequently resorted to as affording a convenient and speedy remedy. Nor are we able to see that any serious objection exists to this method of reaching and restraining a public nuisance. By it a nuisance which is threatened or in progress can be arrested, which cannot be done by proceedings at law; an injunction is more complete in its operation, because it prevents future acts as well as restrains present nuisances; and it affords a more prompt and immediate relief than could be obtained by other process. It is therefore a salutary power if exercised with discretion and confined within reasonable limits. Those limits arel well defined. A court of equity will not interfere by injunction to restrain a public nuisance unless the existence of the nuisance is clearly established upon full and satisfactory evidence. If the proof is conflicting and the injury to the public uncertain or doubtful, the court will withhold its interposition. Ripon v. Hobart, Coop. temp. Brougham, 333, and 3 Myl. & K. 169. Attorney General v. Sheffield Gas Consumers Co. 3 DeGex, Macn. & Gord. 639. 3 Story Eq. Jur. § 924 a.

'We have carefully considered the case made by the relators in support of the prayer for relief contained in the bill, and are clearly of opinion that there is no substantial ground for asking for the interposition of this court. It is not alleged that the defendants intend or threaten to construct their road in, upon *246or across any common highway or street in the town of Sangus, without the permission of the selectmen of that town as required by § 1 of the St. of 1859, c. 202, by which the defendants are incorporated. By the information, answer and proofs it appears that they propose only to construct their track over and upon the Salem and Boston Turnpike, a road constructed and maintained by a corporation duly authorized for that purpose, and charged by law with the care, safety and suitable repairs of said road, so that it may always be in a condition fit for public travel. It also appears that the defendants are acting in the construction of their track with the sanction and assent of the turnpike corporation, in accordance with a contract into which they have entered with that corporation in pursuance of a power expressly granted to them by § 3 of the act aforesaid. To the exercise of this power the consent or sanction of the selectmen of the town is not required. There is no ground therefore for the position that the acts of the defendants are in any respect unauthorized or illegal. Nor are we able to see anything in the evidence which tends to show that construction of the proposed railroad over said turnpike road will create any serious or continued hindrance or obstruction to public travel therein. In the absence of any evidence to the contrary, the reasonable presumption is that the officers of the turnpike corporation will perform their legal duty, and will not assent to or permit any act to be done by the defendants which will seriously interrupt or incommode persons having occasion to use the turnpike road which they are bound to keep in a safe and convenient condition for travel. There is certainly no evidence before us to overcome this presumption or to lead to the inference that any nuisance or public wrong will be committed by the defendants in exercising the rights and privileges conferred upon them by their charter. Upon the case therefore as now presented the order must be Information dismissed, without prejudice.