defendant; telling them, that if they were of that opinion, they should find a verdict for the defendant." But the defendant cannot show in mitigation of damages that the act complained of, amounting to an invasion of the plaintiff's right, was a benefit to the plaintiff, and not an injury; for the plaintiff is not bound to accept a benefit given against his will. He is entitled to any benefits which the defendant's proper use of the stream may incidentally confer upon him,2 and is not bound to exchange one right for another.3 Where prospective damages are allowed, the defendant may show in mitigation that structures erected, or causes set in operation since the suit began, will prevent future injury. So it may be shown that a causeway erected since the suit began will prevent the continuance of flowage.

§ 498. Admissions by a party or declarations by a person interested on either side, must, in order to be admissible as declarations against interest, have been made since his interest accrued.5

§ 499. Evidence as to the nature of the injury must, as

1 Dakin v. Cornish, stated by Alderson, B., in Embrey v. Owen, 6 Exch. 360. So in Elliot v. Fitchburg Railroad Co., 10 Cush. 191 (a case for diversion), the defendants offered evidence tending to prove that one Clark, under whom they claimed had cut ditches through his meadow, which was wet and spongy, to the brook, thereby increasing the flow of water to the brook; and it was further proved that there was no outlet for the water of the meadow, except into the brook below the dam complained of. Metcalf, J., instructed the jury that if, by these ditches, the flow of water was increased equal to the quantity taken out by the defendants, then the defendants were not liable on appeal. Shaw, C. J., said: "The question was not if the defendants had caused a damage to the plantiff, amounting in law to a disturbance of

we have seen, correspond with the allegation. In proving an injury by the flowage of land, where the defendant claimed the right to flow the land to a certain height, the plaintiff was permitted to introduce the declaration of a former owner that a certain stone marked the height of the defendant's right to flow. In order to charge the defendant for an injury done, it is sufficient to show that it was done by his authority, or that he continues it.2 In an action by a canal company for a nuisance in digging clay pits, by which the banks of the canal were injured, it was held incumbent on the plaintiffs to show that the banks were at the time of the damage in such a state as the Act of Parliament required.3 In trespass for entering a close covered with water, and taking fish therefrom, it is held that the ownership of the soil is prima facie evidence of ownership of the fish.+

§ 500. Where a prescriptive right is alleged, it must be proved by evidence of the exercise of such a right for the statutory period, which in the United States is usually twenty years. Evidence is admissible of a user for more than the required time, and also of a user for less than such time, and even of an interrupted use."

§ 501. The claim of a prescriptive right may be defeated by showing it to be under a grant from a temporary occupant, as from the vicar of a parish, who has no power to bind his successor; or the user may be shown to be permis

1 Tyler v. Mather, 9 Gray, 177. See on amendments, ante, § 478.

'Bealey v. Shaw, 6 East, 208, 215; Gilman v. Tilton, 5 N. H. 231. Lord

2 Penruddock's case, 5 Co. 100. Ellenborough, C. J., said: "I take And see Greenl. Evid., § 472.

3 Stafford Canal Co. v. Hallen, 6 B. & C. 317. But see Rex v. Trafford, 1 B. & Ad. 874; 3 Starkie Evid. (7th Am. ed.), 1252.

4 Waters v. Lilley, 4 Píck. 145. 5 Ante, § 329. For the Prescription Act in England, see 2 & 3 Will. 4, c. 71.

it that twenty years exclusive enjoyment of the water in any particular manner affords a conclusive presumption of right in the party so enjoying it, derived from grant or Act of Parliament. But less than twenty years' enjoyment may or may not afford such a presumption, according as it is attended with circumstances to sup

6 Lawson v. Langley, 4 A. & E. 890 port or rebut the right." (a case of way).

8 Wall v. Nixon, 3 Smith, 316.

sive, and evidence may be given of what a former tenant said as to asking permission to have the water, which may be a verbal act, and may be proof or disproof of an exercise of right by one, and an acquiescence in it by the other.1

§ 502. When a prescriptive right is made out, and the opposing party seeks to show a limitation of the right, he has the burden of proof, but may establish the limitation by the same kind of evidence, as of user, as that by which the right itself may be proved. But where a proprietor on one shore appropriates so much of the passing water as he is enabled to control, even the whole of it, by means of structures on his own estate, he can thereby gain no prescriptive right to appropriate more than one-half the same, so long as the opposite proprietor neither uses nor seeks to use any part of the stream to which he is entitled.1

§ 503. To avoid the effect of a grant, the party claiming the prescriptive right may give evidence tending to refer the grant to a different right, subject of course to the rules of evidence on explanation of documents.5 An alleged easement may be defeated by showing that the party claiming it held both the dominant and servient estates by a unity of possession. So where an easement was claimed by the holder of a mill, of entering upon lands in order to repair the banks of a stream, letters which the claimant had written, while lessee of the mill, were held admissible to show the nature of his possession.

§ 504. A former judgment on the question of right involved will, if pleaded, be conclusive of the rights of the parties or those claiming through or under them. This was the rule originally, and it was held with great strictness that

1 Wakeman v. West, 8 C. & P. 105; ante, c. 11.

2 Bliss v. Rice, 17 Pick. 23, 33, 34. 3 Burnham v. Kempton, 44 N. H. 78. 4 Pratt v. Lamson, 2 Allen, 275, 288. 5 Tyler v. Mather, 9 Gray, 177.

6 Clay . Thackrah, 9 C. & P. 47. 7 Vooght v. Winch, 2 B. & Ald. 662 ; Evelyn v. Haynes, per Ld. Mansfield, C. J., cited per Lord Ellenborough, in Outram v. Morewood, 3 East, 365.

if the party claiming the benefit of the judgment did not plead it, but simply offered it in evidence, he thereby, in the language of Abbot, C. J., "consents that the whole matter shall go to a jury, and leaves it open to them to inquire into the same upon evidence, and they are to give their verdict upon the whole evidence submitted to them."1 So it was held that a judgment in an action on the case, disaffirming an exclusive right to a river, is strong evidence in another action trying the same right, but not conclusive. Where the party is not allowed or required to plead specially, the judgment is allowed its full force in estoppel, when given in evidence; and it is now held by several authorities that it will be equally conclusive in all cases, whether pleaded or given in evidence.1

1 Vooght v. Winch, 2 B. & Ald. 662, criticising Lord Mansfield's opinion in Bird v. Randall, 3 Burr. 1353, that in an action on the case a judgment given in evidence is conclusive.

2 Miles v. Rose, 5 Taunt. 705. In case for diversion, it was held that where a question of right has been tried in an action on the case, the record of that trial is evidence in a second action against the same defendant, though there are other defendants, if they all claim under him. Strutt v. Bovingdon, 5 Esp. 56. To the same effect, see Blakemore v. Glamorganshire Canal Co., 1 Gale, 78.

8 Kilheffer v. Herr, 17 S. & R. 319. See Clink v. Thurston, 47 Cal. 21; Gans v. St. Paul Ins. Co., 43 Wis. 108.

4 In 1 Greenl. Evid. § 531, it is said: "Notwithstanding there are many respectable opposing decisions, the weight of authority, at least in the United States, is believed to be in favor of the position that where a former recovery is given in evidence, it is equally conclusive in its effect as if it were specially pleaded by the way of estoppel." And in the notes, Marsh v. Pier, 4 Watts, 288, is relied on, and Kilheffer v. Herr (opinion of

Huston, J.) is cited in support. For a further discussion of the question supporting the wider rule, see Bigelow on Estoppel (3d. ed.), 583. And for a discussion of Vooght v. Winch, 2 B. & Add. 662, upholding it, as deciding that the conclusiveness of the estoppel is waived by not pleading it, see 2 Sm. Lead. Cas., notes to Doe v. Oliver, and Duchess of Kingston's Case (7th ed. 628-9). The reason for the rule in Vooght v. Winch is that the form of the pleadings opens the case for evidence on the merits, and if the case is before the jury on the merits, the question of estoppel is out of the case. The distinction that where, from the nature of the pleadings, recovery cannot be specially pleaded, it shall still be an estoppel, is a clear exception to the general rule. That the law in New York is as stated in the text, see Wood v. Jackson, 8 Wend. 9; Krekeler v. Ritter, 62 N. Y. 372. And that the law was the same in Massachusetts until altered by statute, see Howard v. Mitchell, 14 Mass. 241; Adams v. Barnes, 17 Mass. 365; Bartholomew v. Candee, 14 Pick. 167; Sprague v. Waite, 19 Pick. 455. In Pennsylvania, the common-law rule seems to be in force where there is an

§ 505. If the plaintiff recovers judgment for the erection of a nuisance, and brings a second action for its continuance, he should recite the judgment in his declaration, and state that the action is for a continuance of the same, or the rule applies to both parties that the judgment is only evidence unless averred in pleading. In an action in Pennsylvania for the continuance of a dam overflowing the plaintiff's land, where the plaintiff so averred the former recovery, the court said: "In an issue on a declaration or plea founded on a former judgment, the only proper subject to be submitted to the jury is whether or not the matter in dispute in the present action is the same that was litigated in the former one. With this fact found the court must decide upon the effect of the former judgment."1 In an action for the con

opportunity to plead the judgment. In an action on the case for the continuance of a nuisance by maintaining a dam, the defendant pleaded not guilty, license, and the statute of limitations, and offered in evidence the record of a former trial between the same parties on the same pleas, and the court held that the judgment would not be conclusive unless pleaded. Kilheffer v. Herr, 17 S. & R. 319. This seems to be the decision in that case. It is so stated in the head-note, and so treated in subsequent cases. Marsh v. Pier, 4 Rawle, 273; Kerr v. Chess, 7 Watts, 367; Man v. Drexel, 2 Penn. St. 202. It is cited as an authority for the rule that the judgment is equally conclusive, though not pleaded, in Walton v. Dickerson, 7 Penn. St. 376. But the court said

(per Rogers, J.): "These principles apply only where special pleading is required, for I grant that where the parties are not bound to plead or reply specially, the record of a former recovery is conclusive evidence, binding the plaintiff, the court, and the jury, as in actions of assumpsit and debt." (Relying on the Duchess of Kingston's Case, 20 How. St. Tr. 537.) But, as we have seen, at common law

the greatest latitude was extended to defences in the action on the case, offered under the plea of not guilty; and it would seem that if there were to be any exceptions to the rule, the action on the case would be one; and so it was held in Pennsylvania in Gilchrist v. Bale, 8 Watts, 355, 358. So that the authority of Kilheffer v. Herr, for the point in the text, is by no means unquestioned. In Long v. Long, 5 Watts, 102, the action was on the case for obstructing a stream, and a former judgment was specially pleaded. Rogers, J. (who gave the opinion in Kilheffer v. Herr), in his opinion followed the doctrine stated in the text, and cited the former case as in accord. In Smith v. Elliot, 9 Penn. St. 345, the action was on the case for diverting water from the plaintiff's mill. The defendant pleaded the general issue, and insisted that a former judgment, offered in evidence, was conclusive. Rogers, J., again delivered the opinion. He followed Vooght v. Winch (2 B. & Ald. 662, see supra), and held that the judgment, while admissible, was not conclusive, and again construed Kilheffer v. Herr as in accord.

1 Rockwell v. Langley, 19 Penn. St.