Mr. Justice SWAYNE

delivered the opinion of the court.

The plaintiff' in error brought an action of trespass in the court below to try the title to the real estate in controversy between the parties, and to recover possession. There were numerous defendants. The suit was dismissed, or judgment by default rendered as to all of them but the two who are before us as defendants in error.

The plaintiff sought to recover an undivided third of the premises, which are claimed to be a part of the tract known as the Agostodero, “and the potrero of the Espíritu Santo grant,” situated between the Arroyo Colorado on the north, the Rio Grande on the south, and extending from a thick wood on the west to the lagunes of the sea on the east. The real controversy between the parties was as to the locality of the eastern boundary line of this tract.

The land in controversy lies between that boundary as claimed by the defendants in error, and the sea and lagunes communicating with the sea.

*780 The plaintiff deraigned title by a grant from the authorities of New Spain, of the 26th of September, 1781, to Jose Salvador De la Garza, containing fifty-nine leagues and eleven and a half cabellerias of land.

The defendants claimed uuder a grant made by the authorities of the State of Tamaulipas, by a title of possession issued to Ignaceo Trevino, on the 26th of February, 1829, and confirmed by a final title issued by the governor on the 29th of May, in the same year. The defendants insisted that the western boundary of the land embraced in this grant was the same as the eastern boundary of the tract granted to De la Garza, as they alleged that boundary to be, while, according to the plaintiff’s claim, all the land granted to Trevino, was included in the prior grant to De la Garza. ,

The court instructed the jury substantially:

(1) That the 'question in controversy was the true eastern boundary of the Espiritu Santo tract, and that it was a question of fact to be determined by the jui-y upon the evidence before them.

(2) That it was their duty to consider all the testimony bearing upon the subject.

(8) That if those claiming under the Espiritu Santo grant had never been in possession east of the line claimed by the defendants — had acquiesced in that line, and set up no claim inconsistent with it, until within a comparatively recent period — those facts were proper to be considered by the jury.

At the request of the defendants, the court further charged—

(4) That the grant itself shows that a corner was established at the derrame or slough, 548 cords from the beginning corner, whence a line was run north by the tanque mentioned in the grant to a pocket or small potrero on the Laguna Madre, where another corner was established, and that this was to be'considered the east boundary, unless another one was established by the evidence.

(5) That if Trevino and those claiming under him had held adverse possession up to the line run for the western *781 boundary of the San Martin grant to the time of the commencement of the action — being a period of ten years or more — in good faith under a just title, then the jury should find for the defendants.

(6) That if Trevino and those claiming under him had held adverse possession of the land in controversy for twenty years and more, before'the commencement of the suit, then the jury might presume a válid grant giving title to the land claimed.

(7) That if the jury find there never was any contest before the commencement of this suit between the owners^of the Espíritu Santo grant and Trevino — except as to boundary — being a dispute whether the true line was that run in 1781, or that of 1828 rup for the western boundary of the San Martin grant — and that Trevino and those claiming under him had possession up to 1828, adversely to those claiming the adjoining land in the Espíritu Santo grant, and up to the commencement of the suit, the jury may presume that the land within the line of 1828 belongs to the San Martin grant.

To all these instructions the plaintiff’s counsel excepted.

The plaintiff’s counsel then asked the court to instruct the jury—

(1) That if they find that the Espíritu Santo grant included the land in controversy, then no adverse possession, subsequent to that grant, can authorize the presumption of .another and an adverse grant.

The court refused to give this instruction, and an exception was taken.

The plaintiff’s counsel thereupon asked the court further to instruct the jury—

(2) That a party in possession under an undivided grant of a tract of land, and claiming the whole under a paramount title, is in possession of the whole, and is not affected by an adverse possession of a part, claimed and held under an inferior title or without title, and that the person holding under such inferior title cau have no protection from the statutes of limitation or by prescription.

*782 This instruction was given, but at the request of the counsel for the defendants, it was modified as follows:

(3) That if Trevino and those claiming under him had exclusive possession for twenty years or more, east of the boundary line in dispute, then a grant may be presumed to him, though the Espiritu Santo grant is the elder one, and there has been possession under it west of that line.

To this modified instruction the plaintiff excepted.

The jury found for the defendants, and found further, “ that the eastern boundary line of the Espiritu Santo grant of 1781, is a line commencing at the mouth of the derrame of the tanque on the Rio G-rande, and thence running north to the pocket described in said grant.”

The plaintiff thereupon moved for judgment, non obstante veredicto, for so much of. the premises in controversy as lies east of the line established by the verdict, and west of the line of 1828, being a gore, containing, according to the testimony of one of the witnesses, about nine leagues of land. The court overruled the motion and the plaintiff excepted.

Exceptions were also taken by the plaintiff to the admission and to the exclusion of testimony, which will be stated specifically when we come to consider them.’

It is insisted by the plaintiff in error, that the court erred in construing the documentary evidence relating to the eastern boundary of the Espiritu Santo grant, and that it adopted the theory of the defendants. "We do not so understand the charge as to the latter point. It is somewhat confused both in thought aud language, but its general effect is clear. It left the question to the jury, to be determined according to the evidence, without any controlling instructions upon the subject. They might consistently with the charge have found the line claimed by either party to be the true one. If any error was committed by the court against-the plaintiff, it was in not recognizing, as matter of law, the line insisted upon by her, instead of submitting the question to the jury.

Did the court err in withholding this recognition in the charge ? '

*783 The denunciation, and the identification of the line by the witnesses, describe it as bounded on the coast by the lagunes of the sea. The most important testimony is the survey, the facts attending it, and the subsequent links in the chain of title. The survey was made with great care and formality. It commenced at a watering-place on the Rio Grande, in the southwest corner of the tract. The first line was run 584 cords down the river to a slough, near a tanque, which was filled from the river during high water. This slough was designated “ a natural landmark,” and the denuuciant was ordered to place there an artificial monument. From this point, the next day, the second line was run due north. At the end of 206 cords the surveyor came to the head of one of the “lagunes of the sea” — others were seen to the east. Having gone round the first aud others that succeeded, following always the north course, the line reached a little pocket or meadow made by the lagunes. They were found to extend to the lagunes madres which were formed by the Ai'royo Colorado. Having reached the lagunes madres, and there being nothing before them but water, the surveyor there terminated the line of that day, which was found to be 993 coi’ds in the whole, in length. “ The bend or little pocket before mentioned,” it is said, “ remained as a natural landmark.” An artificial one was also placed there. Owing to natural obstacles, the other two boundary lines were designated without actually running them. The last one terminated at the beginning corner. According to the rule of the Spanish law, where a survey is intended to bound on a stream, a straight line was run from the beginning point to its termination at the slough, and the quantity of land in the bends of the river was ascertained by computation without actual measurement. The slough was about five leagues from the mouth of the r; ver. If it were iutended that the eastern boundary should be the shore of the sea, and of the lagunes connected with it, why was the first line terminated at the slough, and why was a line run due north from there? Why was not the first line extended to the mouth of the river, or to a point nearer to it, and a line run thence to the *784 north. The lagunes of the sea, and not.the shore of the sea, is called for as the boundary on that side. The proof shows that those lagunes could form such a boundary only in part. There is no controversy that the Rio Grande is the south boundary. The proof shows also, that from the mouth of that river north it is several miles to the Boca Chica, which is the first lagune found there. For the intervening distance the shore of the sea, and not lagunes of the sea, must be the boundary according to the claim of the plaintiff' in error. There is nothing which shows that the land lying between the east line as run, and the shore of the sea, and of the lagunes communicating with the 6ea, was included in the computation, or that the grantee had not his full quantity without it.

The attorney of the treasury advised the granting of the “59 sitios de ganadas mayor, and eleven and a half caballerías of the Potrero Espíritu Santo, under the natural outlines which the surveys state.”

The grant itself was of the same quantity of land, specified in the same terms, “ within the limits of the colony of New Santander, and not exceeding its natural boundaries.”

In construing this grant, the attendant and surrounding circumstances, at the time it was made, are competent evidence for the purpose of placing the court in the same situation, and giving it the same advantages for construing the paper, which were possessed by the actors themselves. The object and effect of such evidence are not to contradict or vary the terms of the instrument, but to enable the court to arrive at the proper conclusion as to its meaning and the understanding and intention of the parties. Viewing the subject in this light, we cannot say that the legal effect of the grant is to carry the eastern boundary of the grant to the line contended for by the plaintiff in error. Whether of itself it fixes that boundary, as is insisted by the defendants in error, is a question which in this case it is not necessary to determine. It is enough to say that the instructions on the subject given to the jury were as favorable to the plaintiff as she was entitled to ask. If there was an error, it was *785 not against her. There is nothing of which she has a right to complain. The quantity of laud specified, as well as the boundaries named, and the survey as made, is to be considered. It is by their united light that the proper conclusion is to be reached. Together, we think, they leave little room for doubt as to the intention and effect of the grant.

The finding of the jury that the line surveyed was the east line of the Espíritu Santo grant, renders what was said by the court as to adverse possession and the presumption of a grant immaterial in the case. Night or wrong, those instructions could have done the plaintiff no injury, and, therefore, constitute no ground for disturbing the verdict and judgment.

The instruction given as to the acquiescence of the parties in respect to the line run for a long period, was correct. Tha practical interpretation which the parties, by their conduct, have given to a written instrument in cases like this, •is always admitted, and is entitled to weight. There is no better test of the intention of the instrument. None are less likely to be mistaken. There is no danger of too large an admission. Safer testimony can hardly be presented in relation to any transaction occurring in human affairs.

The motion for a judgment non obstante veredicto assumed as correct a construction of the grant, the opposite of the views we have expressed. "We think it was properly overruled.

Upon the trial the defendants offered in evidence a copy of the record of the original proceedings relating to the Santa Isabel, San Martin, and Buena Vista grants, in surveying which it became necessary to ascertain and fix the east line of the Espíritu Santo grant. The plaintiffs objected to the admission of this testimony, upon the ground, that at the time of the recordation of the documents there was no law which authorized them to be recorded. This objection was overruled, and the plaiutiff excepted. The defendants then proved the genuineness of the signature of Domingo De la Garza, and that he was alcalde of Matamoras in. 1829, *786 They also proved the signatures of the assisting witnesses, and that they were dead.

The plaintiff then objected to the admission of the testimony, upon the further grounds that the document did not appear to be the first copy or testimony issued to the interested party; that it was not proved to be a true or compared copy, of the original protocol, and because it did not appear that the original protocol was duly signed by the proper officer. These objections were also overruled, and the plaintiff exempted.

The questions thus presented are to be decided by the light of the statutory provisions of the State of Texas which bear upon the subject. We have carefully examined those to which our attention has been called. They are found in Arts. 745, 2754, 2758, 2787, 2800, in Hartley’s Digest. The result is, that we are .satisfied that the testimony was properly admitted. It could serve no useful purpose, and would greatly extend this opinion, to go into a full examination of the subject. We deem it sufficient to announce the conclusion at which we have arrived.

The defendants next offered in evidence a copy, proved to be correct, from a paper on file in the archives of the city of Mexico, purporting to be a conveyance from Maria Francesco Cavazos to Miguel Paredes. The plaintiff" objected to its admission, because it did not appear that Francesco Cavazos had ever executed the instrument, or authorized the instrument to be executed for her. We do not deem it necessary to examine the subject in the light of the Spanish law, to which our attention has been called. As the ease was before the jury when the evidence was closed, we think it was entirely immaterial. Its admission or rejection could not change the result. If improperly admitted — a point which we do not find it necessary to consider — it did the plaiutiff no injury, and, therefore, constitutes no reason for reversing the judgment, The power of attorney made by Prieto to Trevino, the will made by Trevino under that authority, and the conveyance by Prieto to De la Garza, offered in evidence by the plaintiff",, and excluded by the *787 court, were clearly irrelevant and incompetent. The ruling of the court was correct.

The same remarks apply to the proceedings before the Supreme Court of Tamaulipas, also offered in evidence by the plaintiff'. They were properly excluded by the court. The title-papers relating to the grant to Trevino were again objected to by the plaintiff upon the grounds: (1) That the laud which appeared to have been granted by the authorities of Tamaulipas was within three littoral leagues of the coast of the' Gulf of Mexico, and that the approbation or consent of the general executive of Mexico was not shown. (2) That the grant appeared on its face to be for more than 125,000 square varas. (8) That it appeared in the proceedings, that a controversy had arisen during the survey as to the ownership of the land affected thereby, and that it had not been settled in the usual and proper manner, but by the' exercise of authority assumed by the executive officers, contrary to the colonization laws of Mexico and Tamaulipas. The court sustained the first objection, and the documents were excluded as showing a valid grant of land, but were allowed to be read in evidence to show boundary and possession. To this qualified admission of the testimony no exception appears in the record. We need not, therefore, consider the learned and elaborate argument submitted by the counsel for the defendants in error to show that the documents were admissible for all purposes, and that the objections of the plaintiff' in error to their admission are untenable.

These are all the exceptions to which our attention has been called.

We find no errof in the record, and the

Judgment is affirmed.