The opinion of the Court was drawn by
Rice, J.This complaint is based upon the provisions of c. 381 of the Special Laws of 1850, being an Act to incorporate the Rockland Water Power Company, for the purpose of conveying to the village of Rockland a supply of pure water for domestic purposes, &c.
The 2d section of the Act provides that the corporation may hold real and personal estate necessary and convenient for the purposes aforesaid, not exceeding in amount seventy-five thousand dollars.
In the 3d section it is provided that " nothing in this Act be taken or construed to prevent the owners of mills, or of *75mill privileges, oil the stream flowing through the outlet of said pond, from using the water thereof in the same manner that they now do or have heretofore done.”
Section six provides for the manner of obtaining redress on the part of mill owners in case they shall be injured by the operations of the corporation.
On the trial of the cause, the defendants offered to prove by Horatio Aldeu, that being possessed, fourteen years ago, and for many years prior to that time, of a clothing mill and other machinery on said Mill river stream, a mile below, the plaintiff’s mill, that the water of that river ran to waste at his dam, in the spring freshets, for the want of sufficient means to retain it at Tolman’s pond, for summer and fall use; that there was not enough left for milling purposes, during the summer and fall months ; and, for want thereof, he could not run said mill much of the time during that season of the year; and that for that reason he removed his works to Camden.
The Court, being informed that there was another stream that united with the Mill river between the plaintiff’s mill and said Alden’s mill, rejected the evidence. Whether other considerations concurred in inducing the Court to exclude the offered evidence does not appear.
The only legitimate purpose perceived for which this testimony could be introduced, was to institute a comparison, by which to determine the flow of the water at the plaintiff’s mill, on different years and at different periods of the year before and since the construction of the defendant’s works. Did the proposed testimony afford any reliable elements from which such a comparison could be made? We think not. It does not appear what portion of the water that ran to waste during the spring freshets, flowed from the west, or from the east branch of the river; nor how. much water was required to run Alden’s mill and other machinery; nor how the requirements of his mill would compare with the requirements of the mill, on the plaintiff’s dam; nor whether the requirements of water, -at his mill, *76were greater or less in the spring or summer and fall; nor whether there is sufficient water now flowing in said stream in the spring or summer to run his mill. In fact there were no elements of comparison offered which could afford any safe or reliable data for the judgment of a jury. Aldrich v. Pelham, 1 Gray, 510.
The evidence offered presented several purely collateral issues, which were both remote and uncertain, affording no reliable ground for comparison if established, and were calculated rather to confuse and mislead the jury than to aid them in coming to a correct conclusion on the matter submitted for their determination. Moulton v. Scruton, 39 Maine, 287.
The defendants also offered to prove, by other witnesses, that in the Mill river stream below said western branch, less water, that could be made useful'to mills on the stream, run prior to 1850, than during the subsequent period, to the present time. This testimony was not less objectionable in its character than that just considered, and for similar reasons. The situation, condition and requirements of the mills below the west branch do not, so far as appears, present such points of similarity to the plaintiff’s mill and privilege, as to afford any reliable data for comparison. Collins v. Dorchester, 6 Conn., 396.
Defendants further offered to prove that the plaintiff’s mill privilege had been increased in value by the improvements they had made at the outlet of Tolman’s pond, and by the manner they had used the water thereof, and called Timothy Williams, who testified that, in 1850, he carefully examined the plaintiff’s mill privilege and mill to ascertain the value thereof, and that he had resided many years in the vicinity of this mill privilege; that he was the owner of real estate in the vicinity; had been an assessor in said town; and was something of a judge of the value of real estate in that vicinity; but had no special knowledge of the value of mills and mill privileges on that stream; that he had never bought, sold, owned or operated a mill. The *77defendants’ counsel inquired of him the value of said mill in 1850. Being objected to on the ground that he was not an expert, the evidence was rejected by the Court.
Witnesses are ordinarily confined to the statement of facts within their own knowledge. There is, however, a class of persons, known in legal proceedings as experts, who are not only permitted to testify to facts within their own knowledge, but who may also give opinions based upon these facts, or facts otherwise proved, or upon hypothetical cases.
An expert is a skilful or experienced person; a person having skill or experience, or peculiar knowledge on certain subjects, or in certain professions; a scientific witness. Heald v. Thing, 45 Maine, 392.
The foundation on which expert testimony rests, is the supposed superior knowledge or experience of the expert in relation to the subject matter upon which he is permitted to give an opinion as evidence. This knowledge must be such as is peculiar to persons of skill and experience in some particular branch of business, or department of science, which is the subject of investigation, and not of such a character as to be open' and common to all persons.
As a person, having such peculiar knowledge, the witness Williams was produced, and his opinion offered in evidence in the case. Was that opinion, tested by the rules applicable to the class of evidence, admissible ? The point to be determined was the value of the plaintiff’s mill and privilege in 1850, when it was examined by the witness. In relation to his knowledge upon this point, he says he " was something of a judge of the value of real estate in that vicinity, but had no special knowledge of the value of mills or mill privileges on that stream; that he never bought, sold, owned or operated a mill.” He thus distinctly negatives the idea that he was possessed of peculiar knowledge or skill in relation to the matter upon which his opinion was desired. It cannot be necessary to cite authorities to show that the opinions of a witness, thus situated, are not admissible in *78evidence as an expert, which is the only ground on which this witness was excluded.
In relation to the requested instructions, which were refused, and to those which were given, no error is perceived.
At common law, the riparian proprietors on a stream are entitled to the natural flow of the water of the stream, without diminution or obstruction, except so far as other parties thereon may have obtained paramount rights to control such flow by grant or prescription. If any such paramount rights have been acquired, they are to be. exercised according to their terms and limitations.
Under our mill Act, riparian proprietors, who are owners of mill sites, may raise a head of water, by the construction of dams, on their own lands, across streams not navigable, for the purpose of working their mills, subject only to.the prior and paramount rights of other proprietor’s. And the head of water thus raised, may be detained a reasonable time for the beneficial, use of such, mills. But the flow of the stream cannot be permanently obstructed, nor the water diverted by such dams, to the injury of the proprietors 'below, nor can the-water be used capriciously to their injury. Each proprietor is entitled to the reasonable use of the water in its natural flow over his land.
The rights of the proprietors of defendants’ mill cannot be measured by the amount of grain they might have to grind within a given time, nor by the peculiar structure of their water wheels, but by the natural flow of the stream as modified by grant or prescription. The defendants could not deal- out the water of the. stream in homeopathic or allopathic doses, to be determined simply by the number and size of the grists that might come to.their mills, or to the character- of'their water wheels, irrespective of their own acquired rights or the rights of the. proprietors below. By the rule contended for by the defendants, they would be enabled to withhold the entire flow of the water for an indefinite period of time, in case no grists came to their mill, or, permit the flow in minute quantities, if their business was *79small and their water wheels required but little water to ■propel them; or, on the other hand, if they were pressed with business, and had wasteful wheels, they would be authorized -to let the water down upon the lower proprietors in floods. Such is not the rule-of law; and, therefore, the requested instructions could not have been properly given, irrespective of the chartered rights of the defendants.
But, further, the requests were inapplicable to the case.
The defendants had no authority, under their Act of incorporation, to operate a gristmill as an independent business. By that Act, the corporation was authorized to hold real and personal estate necessary and convenient for the purpose of conveying to the village of Rockland, a supply of pure water, for domestic purposes, &c.; and the right to recover damages by complaint is given to the mill owners on the stream only in case the corporation, in the exercise of the powers herein granted, shall damage the mill privileges on the stream. If the corporation damaged the mill owners in any other manner than in the exercise of the powers conferred in the Act, by unreasonably or unlawfully diverting or detaining the water of the stream, the remedy of the mill owners would be by some other form of action.
It was manifestly in view of this state of things that the instructions of the Court were given; and, under the circumstances of the case, as presented, they appear to have been full, distinct and apposite.
The only remaining question is, whether the verdict is sufficient in form and substance to determine the rights of the parties and form the basis of a judgment.
The Act of incorporation is very general in its provisions, and the precise manner in which the judgment for damages is to be entered up is not very distinctly indicated. It provides, in case the parties cannot agree, that the mill owner may cause his damages to be ascertained by complaint, in which all parties interested in any particular mill privilege, claiming to have been damaged, shall be joined, to the Supreme Judicial Court at any term held in the county of *80Lincoln, and that said corporation shall be held to answer and plead thereto; and all questions of fact arising upon said pleadings shall be presented to and settled by a jury, unless the parties shall agree to a committee or referees; and that all questions of law shall be settled by the Court as in other civil suits.
The remedy is analogous to that provided under the mill Act for parties whose lands are flowed by the erection of mill-dams; and it is manifestly the intent of the Act under consideration, that damages arising under it shall be determined, as far as practicable, in accordance with the rules which prevail in cases arising under the mill Act.
Under the mill Act, the jury assess the damages to the time of rendering the verdict; but whether that verdict should find the damages in a gross sum or in yearly damages after the date of the complaint, the cases do not entirely concur Com. v. Ellis, 11 Mass., 462; Bryant v. Glidden, 36 Maine, 36. In Bryant v. Glidden, the Court remarks, that "the damages occasioned for three years before the complaint is filed, may be assessed in one aggregate sum. The subsequent damages are to be 'yearly damages,’ for the recovery of which, the owner of the land has a lien from the time of the institution of the original complaint, on the mill and dam. Those damages cannot be found to be different in different years, and be incorporated with those occasioned before the complaint was filed as appears to have been done in this case.” The reason given for this rule is that to find the damages in solido, to the time of the verdict, would deprive the owner of the land of his lien, and other parties of rights secured to them by the statute.
Whether the true point of time from which " yearly damages” under the mill Act should be assessed is not that period when the commissioners, by their report, or the jury by their verdict, determine how far the flowing may be necessary, and what portion of the year such lands ought not to be flowed, has been matter on which different opinions have been entertained. Inasmuch as the flowing under the mill *81Act may be wholly different after it has been regulated by the commissioners from what it had been before, it is apparent that the "yearly damages” may also be different after that period, and therefore there is much force in the suggestion that this would indicate the point of time from which the "yearly damages,” for the future, should be estimated and determined.
But whatever may be the difficulties in establishing a satisfactory rule for yearly damages under the peculiar provisions of the mill Act, no such difficulty exists in this case, as the law gives the complainant no lien, nor does it, in any manner, limit and modify the manner in which the defendants shall exercise their rights, as in cases of flowage. So far, therefore, as this case is concerned, no objection is perceived to entering judgment on the general verdict.
A question may, however, be raised as to the rule for future yearly damages. The Act provides that such judgment shall be the measure of yearly damages, until the parties issue a new complaint to the Court to be filed by either party, &c. The question will naturally arise what final judgment9 It is obvious that the statute is very indefinite on this point. But fortunately the verdict of the jury has furnished the elements for the determination of the question under any conceivable construction. They have found the yearly damages before the date of the complaint, also after the date of the complaint, and until the verdict was rendered. Also the aggregate, for a series of years, to the time the verdict was rendered. From these data, if the parties should not agree, the future yearly damages may readily be established by the Court. But inasmuch as that question is not now distinctly before us, we do not deem it advisable to volunteer an opinion thereon at this time.
Exceptions overruled, and Judgment on the verdict.
Cutting, May, Davis, Goodenow and Kent, JJ., concurred.