This is an action of tort, to recover damage, done to the plaintiff, in the use of his mills, situated on Swift River, so called, by the defendants, in erecting on their own land on the same river, and above the mills of the plaintiff, mills and manufactories of greater magnitude than were adapted and appropriate to the size and capacity of said river, and to the quantity of water flowing therein, and using the water of said river in an unreasonable manner, and detaining the same in a pond or reservoir, for unreasonable periods of time, both in the day and night, and discharging the same in excessive quantities, so that much of it ran to waste and was lost to the plaintiff, depriving him of the water power.
This case having been submitted to referees, by rule of court, their report, by agreement of parties, is now to be taken as a statement of facts. It involves the relative rights of riparian proprietors on the same stream or watercourse, as it passes through their respective lands, to the use of the power of such current, for hydraulic purposes. These rights depend mainh *450upon the rules and principles of the common law, somewhat altered and modified by the series of enactments known as the mill acts of Massachusetts. This rule is, that every proprietor of land through which a watercourse runs has a right to the use of the impelling force of the current, or what is more familiarly called the head and fall of the current, for mill purposes, so far as they exist on his own land, if there be any such head and fall within his own limits. If the water flows at nearly a level, there will be no such available head and fall. If the descent be very rapid, there will be such head and fall, and of course mill sites or privileges, at short distances from each other. If the descent be gentle and regular, and the land of a proprietor not extensive, the head and fall on his own land may be quite insufficient for practical use, for mill purposes. This latter consideration probably led to an early modification of the common law in Massachusetts, by a provision that such a proprietor might erect a dam on his own land and raise a head of water to his own best advantage, although it might raise the water in the bed of the river, beyond and above the limits of his own land; notwithstanding it might flow back, by such rise in the bed of the river, upon the land of other proprietors — with a provision for a compensation in damages.
These provisions have effected a change in the common law to this extent: By the common law,the rights of each successive riparian proprietor to the reasonable use of the mill power of the stream are equal; each has a right to a reasonable use of it as it passes through his own land only, with a right incident thereto to erect such dams, canals, sluices and water ways, as to fit it for the actual working of mills. By the right given by the mill acts to any proprietor to flow back beyond his own limits, the common law is changed to some extent. Before any mills are erected, the right of each proprietor is the same; it is a right to appropriate the power of the stream, by the actual erection of a mill, though the head and fall within the limits of his own land are insufficient, and, in order to get sufficient head he raises his dam so as to flow beyond his own limits, The necessary consequence is, that when one proprietor, undei *451the common right, has in fact appropriated the power, the proprietor below is so far restricted in his right of appropriation, that he cannot erect a mill on his own land, and flow back the water, to the destruction of the mill already erected by authority of law. This priority of first possession necessarily arises from the nature of appropriation ; where two or more men have an equal right to appropriate, and where the actual appropriation by one necessarily excludes all others, the first in time is the first in right. Cary v. Daniels, 8 Met. 466.
By the rule that all proprietors of land through which a watercourse passes have an equal right to the use of the power of the stream for mill purposes, it is not to be understood that each or any one has a right to the natural flow of the stream in the manner in which it ran originally, or as it would run if no mill were erected on it, or to be worked by it; in its mere natural flow, it affords no power. Dams must be made to raise it, and canals and sluices to conduct, apply and discharge it. The right to erect these works, and to change the natural mode of the flow of the current, is incident to the right of applying it to the working of mills, and this right therefore is common to every riparian proprietor. Each therefore must exercise his own reasonable right with a just regard to the like reasonable use by all others. The mere erection of a dam, and the use of the water in driving wheels, must necessarily derange its steady and constant natural flow, and substitute a different manner, as to the time and mode of holding it up and letting it down. So far as such mode is reasonably incidental to the use of the stream for mill purposes, it is the right of the proprietor, and constitutes, in part, the mill privilege which the law gives him.
In examining the facts in the present case, the court are of opinion that the plaintiff acquired no prior right, by prescription or otherwise, to any particular mode of using the water. It must be some use inconsistent with, and therefore adverse to the right of others, which can be acquired by prescription, such as diverting the water from its natural course. So far as he uses it equally, and in a manner consistent with the equal and common right of others, he makes no adverse use, and ac*452quires no right adverse to theirs. It appears that the plaintiff had a great abundance of water, beyond what was necessary for working his own mills, and could work them day or night, without encroaching on the right of any other, above or below.
We are also of opinion, that nothing stated in the facts, as to the manner in which the parties respectively acquired their rights to their respective estates, affects the right of either against the other, as millowners; but that the rights of the parties respectively, as owners of mills, must depend upon the rules of law, regulating the rights of riparian owners, as established in this commonwealth.
Upon the facts agreed, the court are of opinion, that the defendants did not exceed their just right in the use of this water power.
It appears that the defendants built a substantial dam across the river, that the water was drawn into their manufactory by a canal, and, after being run upon their wheels, was wholly returned to the bed of the stream above the plaintiff’s mills; and that the works of the defendants “ were of such magnitude only as were adapted to the size and capacity of the stream and to the quantity of water usually flowing therein.” It also appears that “the defendants have caused no further disturbance or interruption of the flow of water to the plaintiff’s mills, than was necessary and unavoidable in and by the reasonable and proper use of it, for the propelling and working of the defendants’ factory.” What is a reasonable use of water power may often be a difficult question, depending upon a great variety of circumstances ; somewhat upon usage, upon the state of mechanical and manufacturing advancement. Usage is some proof of what is considered a reasonable and proper use of that which is a common right; because it affords evidence of the tacit consent of all parties-interested, to the general convenience of such use. The circumstances above stated, we think, are decisive of the present case, and show that the defendants made no other than a reasonable use of the water; and if this did interfere at times, with the use which the plaintiff might have made of the water *453if the defendants had had no occasion to use it, it was damnum absque injuria.
But the referees who report these facts further say, that in making their estimate of the suitableness of the works to the stream, they “ have had reference to the ordinary volume and flow of the water, at different seasons ; but no reference to the plaintiff’s necessities for water in times of extraordinary and extreme drought, when the stream, though sufficient to operate the plaintiff’s mills, would be insufficient to operate the defendants’ factory.” By this we understand that they did not take into consideration the plaintiff’s necessities, arising from his peculiar business, the height of his pond, the capacity of his reservoir and the nature and character of his works. One of the grounds of the plaintiff’s complaint was, that when the water was very low, in time of drought, and the defendants detained it a few hours, or in one instance a whole day, to raise the water to a sufficient height to work their own factory, it came to the plaintiff’s mill faster than he could use it, and ran to waste over his dam. If it was so, it was because he had works not adapted to the entire or the best use of the stream ; because his dam was too low, his reservoir not of sufficient capacity, or other cause, by which he was prevented from making the best use of the power of the water, when very low by reason of drought. If there was a loss of water at such times and from such cause, it was not one for which the defendants were responsible.
As there was no detention of the water in ordinary stages of water, and no other detention of the water by the defendants, in times of extreme drought, than what was necessary to the reasonable use of their own mills, we are of opinion that it was not their duty, in point of law, to open their gates, or leave them open without using the amount to such extent as they might, merely because the plaintiff’s works were of such a char acter that his necessities required such flow of the water.
Judgment for the defendcmts