after stating''the case, delivered the opinion of the court.
Only two questions are discussed in the brief, and only those will be considered:
(1) Did the trial court err in its instructions- to the jury, and, if so-, was the error prejudicial? (2) Did the defendant establish a right to the use of the waters-of Black Tail Deer creek by adverse user ?
1. It is contended that the court erred in its instructions with reference to the question of the relationship- of landlord and tenant, alleged to have; existed between thei Basin Flume Company, predecessor in interest of tire defendant water corn-company, and Olin. and Talbott, predecessors- of Talbott and Thompson, two of the plaintiffs.
Instruction No. S, above, given at the instance of the plaintiffs, and No. 6, above; given, at the instance of the defendant, are absolutely contradictory. Section 37, First Division, Compiled! Statutes- of 18S7, is copied in instruction No. 7, above. The construction given this section by the court in instruction No. 8, above, is clearly erroneous. The section deals with the question of possession, while the instruction erroneously applies the doctrine to- the relationship of landlord and tenant. Under that section, so long as the tenant is holding possession of property obtained from his landlord while the relationship of landlord and tenant exists, the- doctrine of the section applies; but, as soon as the tenant delivers up his possession and the relationship is fully terminated, the section ceases to- have any application, and an adverse holding can therefore be immediately initiated by a hostile re-entry into such possession.
*25The testimony shows that, if the relationship of landlord and tenant ever existed at all, it existed only for a few days in 1886, when the water was turned back to* the predecessors of plaintiffs, and the relationship! fnl-ly terminated.
However, that error is Avithout prejudice in this instance, for, notwithstanding such, instructions, the court had admitted all the testimony offered on behalf of the defendant tending to prove its adverse user; at least, no complaint is hero made that any testimony offered in that behalf Avas excluded. The matter AA-as treated in the district court throughout as a suit in equity. In fact, the opening’ statement in appellant’s brief is, “This is an equitable action.” And Avithout disposing’ of the question Avhether in fact it is an action at law, or a suit in equity, it is sufficient to say that when a cause has been, tried upon a certain Avell-defined theory, neither party Avill be heard in, this court, on oral argument, for the first time, to assume a position antagonistic to such theory. (Harris v. Llloyd, 11 Mont. 390, 28 Pac. 136, 28 Am. St. Rep. 475; Leavenworth N. & S. Co. v. Curtan, 51 Kan. 432, 33 Pac. 297; Davis v. Jacoby, 54 Minn. 144, 55 N. W. 908.) .
Assuming, then, that the cause AA'as one in equity, the findings of the jury are merely advisory to the court, and errors in instructions given to the jury are Avithout prejudice. (Lawlor v. Kemper, 20 Mont. 13, 49 Pac. 398; Haggin v. Saile, 23 Mont. 375, 59 Pac. 154; Wetzstein v. Largey, 27 Mont. 212, 70 Pac. 717.) In this instance the whole matter of the relationship* of landlord and tenant, upon, Avhich, the erroneous instructions Avere given, can be entirely eliminated from consideration. The allegations of the complaint with reference to it Avere insufficient to constitute a plea of estoppel, and the consideration given the subject by the trial court so completely failed to affect in any manner the substantial merits of the controversy that it is, not deemed necessary to remand the cause in order that all reference to, it be eliminated from the decree: No contention is made here that any evidence Avas offered on behalf of the defendant tending to establish its right by prior appropri*26ation. The plaintiffs apparently relied upon their claim as prior appropriators, and the defendant upon title by adverse user.
2. The testimony offered on behalf of the defendant shows that for five yea^s prior to the commencement of this action the defendant and its predecessor in interest had used some, and at certain times all, of thei waters of Black Tail Deer creek, at least a portion of every year; but there is no> showing whatever that such use was had at any time when these plaintiffs had need of the water, or that the use of the water by the defendant interfered with its use by the plaintiffs prior to the year 1891, while this action was commenced in 1893. In order that the use of the water by the defendant company might ripen into a right by1 adverse user, as against the plaintiffs, such use must have been open, notorious, continuous, adverse and exclusive, under’ a claim of right. (Long on Irrigation, Sec. 90, p. 160; Cox v. Clough, 70 Cal. 345, 11 Pac. 732.) It is not sufficient for defendant company to show that its use of the water was open, notorious and continuous, but it must show that such use was adverse — that is, its use of the water must have been such an invasion of plaintiffs’ right to its use, as that they could have maintained an action against the defendant for such invasion; and such adverse use must have been continuous for a period of time equal to' the period of the statute of limitations, which in this instance was five years. (Yankee Jim's Union Water Co. v. Crary, 25 Cal. 504, 85 Am. Dec. 145.) This doctrine is too well established now to- be open to serious controversy. (Long on Irrigation, Sec. 90; Faulkner v. Rondoni, 104 Cal. 140, 37 Pac. 883; Smith v. Logan, 18 Nev. 149, 1 Pac. 678 ; Alta L. & W. Co. v. Hancock, 85 Cal. 219, 24 Pac. 645, 20 Am. St. Rep. 217.)
The plaintiffs had use for thei water only for agricultural and mining purposes, and, when not so using it, the law required them to turn, it back into' the stream for the use of this defendant, or any other person or corporation which might have a right to its use. No' irse of water by a subsequent appropriator can *27bo said to be adverse to the right of a prior appropriator, unless such use deprives the prior appropriator of it when he has actual need of it. To take the water when the prior appropriator has no use for it, invades no¡ right of his> and cannot even initiate a claim adverse to him. “When there is sufficient water in the river to supply all parties, there can be no such thing as adverse use of the water to start thei statute of limitations running. Each is entitled to the use of the xvater, and it is- only xvhen the xvater becomes so scarce that all of the- parties cannot be supplied, and that one appropriator takes water which by priority belongs to another appropriator, that there is an adverse use.” (Egan v. Estrada (Ariz.), 56 Pac. 721; Anaheim Water Company v. Semi-Tropic Water Company, 64 Cal. 185, 30 Pac. 623.)
The evidence introduced on behalf of the plaintiffs tended to show! that they had sufficient xvater to- supply their, needs until 1891. The evidence failed to establish á right in the defendant to the use of the xvater by adverse user, while it is amply sufficient to sustain the findings of the1 court that the plaintiffs are prior appropriators, and, as such, entitled to- the use of the water as against any claim of the defendant.
The judgment and order appealed from are affirmed.
Affirmed.