Fostek, J.
The only question presented by these exceptions *309is whether the evidence offered by the defendants amounted to a justification of the act complained of; the setting back of water from the defendants’ dam below upon the plaintiff’s mill-wheel above. The issue presented by the answer and the evidence was whether the use of the stream actually made by the defendants was a rightful one or not. The defendants’ right to keep up the water from October to May was not in controversy. They claimed also a prescriptive right to do so by flash-boards from May to October so far as they could without injury to the grass on the meadows. We need not consider whether such a right as this, to flow one man’s mill-wheel when it will not injure another man’s grass, is definite enough to be established by prescription. Assuming it to be so, the evidence falls far short of supporting the claim. The practice of nailing on flash-boards for short periods, when the water did not hurt the grass, and a single instance of refusing to draw off the water upon the plaintiff’s request, are all the circumstances relied upon. The occasional use of flash-boards in the summer for short periods as an exception to the general rule not to keep them up during that part of the year, does not amount to the open, uninterrupted and adverse use necessary to establish a prescriptive right. Such acts are merely occasional torts, perhaps not at once resisted only because they were deemed unimportant and' did but a trifling injury to the plaintiff. They would not support a verdict upon the affirmative proposition of fact which the defendants were undertaking to maintain. And such was the ruling of the judge at the trial. Exceptions overruled.