Ladd, J.
i. killing stock’ spec-iai finding, The highway, where it crosses the railroad, is forty-five feet wide. The plaintiff relied on circumstances tending to show that the horse was struck by the engine while on the track fifty-sis feet north of the center of the crossing. The defendant •engineer and fireman testified that the collision occurred on the crossing. The jury rejected their evidence as unreliable, by an answer to a special interrogatory that it did not happen at that place. This was tantamount to a finding that the horse was struck fifty-six feet north of *474the center of the crossing, for, under the evidence, the collision must have occurred at one of these two places. Appellant argues that the evidence supporting this conclusion is unreliable, and in any event not inconsistent with the contention that the animal was hit by the engine-on the crossing. The probative force of circumstantial evidence requires no vindication at our hands, nor is it necessary to spend any time in demonstrating that the-finding of horse tracks leading from a pasture to a point-fifty-sis feet from a crossing, and there terminating, and the finding of the body of the horse twelve feet beyond, in-the ditch at the side of the track, is inconsistent with the testimony that he was killed by the engine at the crossing.
2. Evidence: of-witness, The testimony that the tracks were of a horse, and indicated his motion — whether walking, running, or’ jumping — was clearly admissible. It was of facts somewhat in the nature of conclusions. These could not well be so described as to convey to the mind of the jury the inference of precisely what the horse was doing, and therefore the witness, as a part of the description, was properly allowed to state whether they were similar to tracks when walking or when running or jumping. “It is competent for a witness to testify to his conclusion, when the matter to which the testimony relates cannot be reproduced or described to the jury precisely as it appeared to the witness at the time.” Yahn v. City of Ottumwa, 60 Iowa, 429; Bizer v. Bizer, 110 Iowa, 248; Stewart v. Anderson, 111 Iowa, 329.
3. evidence íofaiitynof accident. II. It was important to ascertain the distance of the horse, when struck, from the north cattle guard and the center of the highway crossing. To enable him to measure such distance, a. witness was allowed to testify that plaintiff pointed out certain depressions scooped out in the track, from which he measured. This was admissible as connecting the measurements with the locality of the collision, for *475plaintiff’s testimony tended’to show that the horse must have caused these when struck by the engine. Ward v. Ry. Co., 97 Iowa, 54.
4. eight of way fenoe‘ III. From a point where the east right of way fence intersects the wing fence running north from the trestle to the north west corner of the pasture, the fence belonged to plaintiff, and was somewhat in the right of way;* and as, according to plaintiff’s theory,' the horse passed directly over this fence in the right of way to the point where it was killed, the defendant insists it is not liable, for that fence was not shown to be defective, and, even if so,' the loss was owing to plaintiff’s negligence. The character of this fence does not appear, save that it was constructed of posts and wire. No evidence of its sufficiency to turn stock was introduced. If there were any agreement, express or implied, that the landowner should erect the right of way fence or keep it in repair, the record does not disclose it. The mere fact that he had maintained some kind of a fence there for fifteen years did riot, alone, warrant such an inference. The company had the right to fence its track at the point where the horse escaped. It failed to do so. Upon proof of this, and the injury to the animal by one of its engines passing over the track, a prima iaoie case was made out for plaintiff. Code, section 2055; Brentner v. C., M. & St. P. R. Co., 68 Iowa, 530; Manwell v. B., C. R. & N. R. Co., 80 Iowa, 662; Wall v. Des Moines, M. & N. R. Co., 89 Iowa, 193; Norman v. C. & N. W. R. Co., 110 Iowa, 283. If defendant were relieved from the duty of e.-eoting or maintaining a fence by the action of plaintiff, or had other excuse, the burden of proof was upon it both to plead and establish such defense. Kingsbury v. C., M. & St. P. R. Co., 104 Iowa, 63. As said, the voluntary construction of some kind of a fence by the landowner along the right of way did not excuse the company from erecting that required by law. Louisville, etc., R. Co. v. *476White, 94 Ind. 257; Norfolk, etc., R. Co. v. McGavock's Admr's, 90 Va. 507 (18 S. E. Rep. 909). To relieve the defendant from responsibility, it must- not only appear that the fence, in its construction, was sufficient, but at the time complained of it was in a fair state of repair. Jefferson, etc., R. Co. v. Sullivan, 38 Ind. 262. If this were shown, the company would not be liable, even though the fence may have been erected by a mere- volunteer. Hovorka v. Minneapolis, Etc., R. Co., 31, Minn. 221 (17 N. W. Rep. 376); 2 Thompson, Negligence, section 2097. As no agreement with plaintiff to erect or maintain the right of way fence was proven, and a sufficient fence was not shown to have been erected by him, the escape of the horse into the right of way must; be held to have been owing to defendant’s failure to comply with the statute.
s. negligence of train. IV. Appellant also argues that the collision was not shown to have occurred beyond the east boundary line of the highway; that is, where the company had the right to fence. Waiving the question as to whether this was necessary, we think the evidence is otherwise. The grade at the crossing was about eight feet high. The approaches to the crossing were twelve feet wide, and the planks sixteen feet long. The horse, when hit, must have been fifty-six feet from the center of these planks, which, in the absence of evidence, will be presumed also to be in the center of the highway. It was the duty of the company to construct this crossing. Code, section 2054. Farley v. C., R. I. & P. R. Co., 42 Iowa, 234. It had been maintained at the identical place for thirty-five years. In the absence of some controlling reason to the contrary, highways are to be improved so that travel shall pass along the middle line of the land appropriated therefor. Quinton v. Burton, 61 Iowa, 471. The company cannot well complain of the assumption that it constructed the crossing at the, place exacted by law. The statute required the cattle guards and fence to be *477placed along the line of highway. Andre v. C. & N. W. R. Co., 30 Iowa, 107. These should then have been twenty-two and one-half feet from the center of the crossing. That the horse was struck beyond a line twenty-two and one-half feet from the center of the crossing, if not on the crossing as contended by defendant, the record leaves no doubt. In returning a verdict for plaintiff, and finding that the horse was not hit on the crossing, the jury necessarily so concluded. The collision must have occurred, if the finding of the jury is to be accepted, where the defendant had t) e right to fence, and failed to do so. This being true, it is immaterial whether the defendant was negligent in the respects alleged, and the errors assigned in relation thereto, if conceded to be such, were without prejudice.— Aeeirmed.