Weavee., J.
The defendant corporation is engaged in the business of killing, curing, packing, . and selling meats at Sioux City, Iowa. About two or three weeks prior to the date of the accident Emil Lunde, a boy of about seventeen years, was engaged to labor in the engine-room' of the defendant’s works. Lunde had no prior experience in such service, but is described - as a steady, sober, careful workman. Among the duties required of him was the oiling of the- machinery or of certain portions of it. Included in this machinery was an engine, to which was attached a large and heavy fly wheel about sixteen feet in diameter, the lower part revolving in a pit-in the floor. On the south side of the fly wheel and parallel with it was an apparatus known as the ice machine. Between the wheel and the ice machine there was a narrow passageway, intercepted or obstructed midway by the south axle of -the fly wheel and the bearing in which it rested. To oil this bearing the usual and appropriate method was for the employe to enter this passageway from the east end. Tim wheel pit along this end of the passageway was guarded by a double line of gas pipe rails, fastened to posts standing close to the edge. The upper rail was about thirty-six inches, and the lower twenty-five inches above the floor surface. The passage was floored with cement, and was about nine and a half inches in width. The edge of the rim of the wheel hung within about five inches of the guard rail, but the spokes not *691being of thickness equal to the width of the rim were twelve inches from the edge of the pit. At the entrance, and nearly opposite the rim of the wheel, this passage was further narrowed by a shive projecting slightly over the path, and carrying a slowly moving rope which operated an oil pump. After passing this point the ice machine curved slightly away from the cement path, giving a somewhat wider passage for the remainder of the way. The width does not definitely appear in the'record, but is estimated by some witnesses as two feet or a little more. The testimony also tends to show that in passing the narrowest point a person entering from the east was required to step in sidewise to avoid contact with the shive and rope above mentioned, and -that for the remainder of the distance along the cement path he could walk straight ahead, being careful to step one foot directly ahead of •the other. There was sometimes frost on the ice box, pipes, and machinery, and a pail of oil sometimes stood on the frame. At times the path was a little oily. The fly wheel pit and passage west of the axle was not guarded by railing or otherwise, and employes were not expected to enter from that side to oil the bearings.' Lunde worked on the night shift, and on the night of June 13, 1907, was on duty with the engineer, one Stephenson. It was part of his duty to oil the fly wheel bearings, taking the course we have already indicated. It was also proper for him to inspect the bearings at times to ascertain whether they were becoming heated. About midnight of the day named Lunde was alone in the vicinity of the fly wheel and ice machine. The engineer, Stephenson, being engaged some distance away, heard an unusual sound, and coming to the place found Lunde lying on the floor with broken legs and arms and other severe injuries, of which he soon died. He was not wholly unconscious when discovered, and when asked how the accident occurred, responded, “I don’t know,” but beyond this he *692seems to have been unable to speak. The top guard rail, which had been straight prior to the accident was found to be bent down, and slightly out near the east end and about two feet from the rim of the fly wheel. Lunde’s shoes were torn across the toe and doubled back. His clothes were not torn, but were more or less saturated with oil. A little blood was found on the ice pipe east and south of the fly wheel, in the direction of the place where the body was found. The rope running on the shive at the east entrance to. the passage was pulled off and hanging in the wheel pit. Later Lunde’s wrench was found in the pit.
The petition charges the defendant with negligence leading to the death of the intestate, in the following particulars: First, in failing to furnish the deceased a safe place to work; second, in failing to properly warn or instruct the deceased as to the proper manner of doing the work, and how to avoid danger in its performance. The answer denies all negligence on the part of the defendant, alleges contributory negligence on the part of the deceased, and that he assumed the risk of the danger to which he was exposed.
1. New Trial. I. A verdict having been returned for the plaintiff, defendant moved for a new trial because of the alleged misconduct of a juror, one Fred Hewitt. The motion is supported by the affidavit of appellant’s counsel to the effect that, in his examination as to his qualification to sit as a juror, said Hewitt stated that he had no bias or prejudice in cases of this nature; that he could, and would, give the case impartial and fair consideration, and return a fair verdict upon the evidence and the law as given by the court. Immediately after the return of the verdict another jury was being impaneled for the trial of a personal injury case against the same defendant, and, the same juror being called into the box, he was again subjected to a similar *693examination, and answered that he had a bias and prejudice in this class of cases, which might or would have an influence on the, verdict, on which answers a challenge to the juror was sustained. Counter affidavits were submitted tending to show that the juror was not in fact interrogated as to his personal feelings or prejudices as to cases of this kind in general, and that, so far as the juror had in fact any bias or prejudice, it was in favor of the defense. The overruling of this motion is assigned for error. The assignment is not well grounded. No bill of exceptions or other record was preserved of the examination of the juror, and the matter and manner of it is presented upon affidavits which put the alleged misconduct of the juror in issue, and, the finding of the court upon the disputed facts not being without support in the evidence, we cannot disturb it.
2. Same: misconduct of juror. Even if this were not the case, there is no such necessary discrepancy between the two statements of the juror as to justify us in holding him guilty 0f misconduct such as will vitiate the verdict in the earlier case.
3. Master and servant: failure to warn. II. The court submitted to the jury, with appropriate instructions, the question of the defendant’s alleged negligence in failing to properly instruct and warn the deceased. This is said to be , „ , , , ,, erroneous, because of the entire lack 01 evidence to support the charge. We do not so read the record. Hiere was evidence, on the part of both the plaintiff and defendant, tending to show the nature and extent of the instructions given. They were mostly of a general nature, and few of a specific character. It was not for the trial court, nor is it for this court, to say that as a matter of law such instructions were sufficient, and filled the full measure of the defendant’s duty in the premises. Whether such was the case requires a consideration of the age and experience of the *694deceased, the peculiar hazard to which his service ‘exposed him, whether they were patent'to his observation as an ordinarily prudent person, and all the pertinent circumstances surrounding the transaction, and it was clearly within the province of the jury to draw therefrom the inference or conclusion whether due care had been exercised. There was no error in submitting this- issue to the verdict of the jury.
4. Contributory negligence: instructions. III. The defendant asked the court to instruct the jury that, if the deceased was injured by reason of going in between the frame of the ice machine and the fly wheel on the west side, where there were no guards, he would be guilty of contributory negligence, and plaintiff could therefore not recover. The request was refused. The refusal was not erroneous. The court on its own motion carefully charged the jury that they could not find for the plaintiff unless they were satisfied from all the evidence that intestate was exercising reasonable care for his own safety, and did not by his own negligence in any way contribute to his injury, and we think it would have been an invasion of the province of the jury to charge that the mere fact of going between the wheel and frame on the west side, no matter for what purpose or under what circumstances, was negligence as a matter of law. 'Moreover, there is no evidence whatever that he did enter the passage on the west side; and, if it be true, as argued, that there was no occasion for his going there, and his duty did not call him there, his administratrix is entitled to the benefit of the presumption that he did not thus recklessly and unnecessarily expose himself to deadly peril.
*6955. Instinct of self-preservation: instructions. IV*694. It is averred that the court erroneously placed upon defendant the burden of showing that the deceased did not exercise due care for his own safety. This objection is based upon a misconception of the force and effect of the charge given by the court. It did not re*695lieve the plaintiff from the burden of showing due eare on the part of deceased. In the fifth paragraph the jury was told that the mere fact that Emil Lunde was hilled while in defendant’s service and by its machinery afforded no presumption of defendant’s negligence, and that plaintiff was bound to show, not only that such accident was chargeable to defendant’s negligence, but also that he did not, by his own conduct, negligence, or carelessness, contribute in any way to his injury. The same thought was repeated in the tenth paragraph. In the sixth, seventh, eighth, and ninth paragraphs the law and its application to the question of assumed risk were fully and fairly stated. The eleventh paragraph — the one on which the complaint of the appellant is based — was in the following words:
Upon the question of plaintiff’s intestate’s contributory negligence you are instructed that, where there are no eyewitnesses as to the manner in which he was conducting himself at the time he received the injuries, the law presumes that he was exercising such care and caution as men of ordinary prudence, judgment, and discretion exercise under like circumstances and in relation to the same matters, unless the facts and circumstances shown upon the trial negative such presumption; and you should indulge in such presumption in his favor, unless the facts and circumstances developed on the trial negative such presumption.
This in no manner relieves the plaintiff from the burden of proving the freedom of the deceased from contributory negligence, but states the rule, now well settled, that this burden may be met, and the fact of due care may be established, prima facie by showing that when last seen he was acting in the line of his duty, without any apparent negligence, and that there is no living witness or direct testimony as to the manner in which his death occurred. Under such circumstances, for want of *696better evidence, the natural caution and instinct of self-preservation which lead the normal and sane human being to avoid injury and death are i'ecognized by this and many other courts as affording ground for the presumption or inference that the deceased did not negligently expose himself to the injury which he suffered, unless there be proof of other facts and circumstances which negative such conclusion. The decision in Bell v. Clarion, 113 Iowa, 126, on which appellant relies is not inconsistent with the instruction now being considered. The instruction there held to be erroneous xvas to the effect that in such cases the burden of proof, on the question of contributory negligence, is shifted to the defendant, and that the deceased would be held to have exercised due ca,re until the conclusion is “overcome by evidence that satisfies the jxxry that he was negligent.” The instruction in the present case not only does not relieve the plaintiff from the operation of the ordinary rule, which requires her to prove by competent evidence both the negligence of the defendant and the' absence of contributory negligence by the deceased, but on the contrary, the charge given the jury is carefully framed to prevent any confusion or misunderstanding on this point. It is also in entire harmony with the law as laid down in numerous cases. Greenleaf v. R. R. Co., 29 Iowa, 14; Way v. R. R. Co., 40 Iowa, 341; Hopkins v. Knapp, 92 Iowa, 328; Salyers v. Monroe, 104 Iowa, 74; Dalton v. R. R. Co., 104 Iowa, 26; Crawford v. R. R. Co., 109 Iowa, 433; Baker v. R. R. Co., 95 Iowa, 171; Mynning v. R. R. Co., 64 Mich. 93 (31 N. W. 147, 8 Am. St. Rep. 804); McBride v. R. R. Co., 19 Or. 64 (23 Pac. 814) ; Lymen v. R. R. Co., 66 N. H. 200 (20 Atl. 976, 11 L. R. A. 364); Penn. R. R. Co. v. Weber, 76 Pa. 157 (18 Am. Rep. 407); Cassidy v. Angell, 12 R. I. 447 (34 Am. Rep. .690); Johnson v. R. R. Co., 20 N. Y. 65 (75 Am. Dec. 375); Railway Co. v. Landrigan, 191 U. S. 461 (24 Sup. Ct. *697137, 48 L. Ed. 262) ; Huntress v. R. R. Co., 66 N. H. 185 (34 Atl. 154, 49 Am. St. Rep. 600) ; Texas R. R. Co. v. Gentry, 163 U. S. 353 (16 Sup. Ct. 1104, 41 L. Ed. 186); Grimm v. Power Co. (Neb), 114 N. W. 769.
6. Negligence:assumption of risk. V. Counsel for appellant insist, also, that under the evidence the court should have held, as a matter of law, that deceased bad assumed the risk of the injury which he suffered. In support of this contention it is said that deceased had been employed in the place a long time, that the dangers incident thereto were open to his view, and that, as an ordinarily reasonable and prudent person, he ought to have discovered them, and his administratrix will not be heard to deny his knowledge of them. It may readily be admitted that there were manifest elements of danger incident to this employment which must have been as patent to this young man, even though inexperienced, as to older and more experienced servants about the premises. For instance, a boy of ordinary intelligence would need no one to tell him that he could not enter the wheel pit, or come in contact with the wheel while in motion, without endangering his life. But the duty imposed upon him required him to walk along a narrow path separated from this place of danger by a few inches only, and he had a right to assume that his employer had exercised reasonable care to make the passage safe, unless the employer’s neglect, if any, in this respect was so open and obvious that deceased ought to have discovered it and abandoned the employment, and this is not so clear that we are .able to dispose of it as a question of law. It is not correct to say, as counsel does, that the deceased had worked in this capacity for a long time, and that we may fairly presume that he was fully aware of all the matters and things now charged against the defendant as negligence. His service in this work did not exceed nineteen days, he was a mere apprentice, just learning the work *698or trade of stationary engineering, and it would be an undue extension of the province of the court to say as a matter of law that in this time he ought to have learned and comprehended, in all its essential features, the risk to which he was exposed. Fori instance, experienced witnesses testified that the usual and proper wav guard such a wheel and pit was to set the railin'-; ...ick several inches from the brink of the opening in fche floor, and that to avoid danger of slipping into the opening the lower bar should be placed not more than fifteen inches above the floor, while in defendant’s engine room the railing was set flush with the edge of the pit, and the lower bar was twenty-five inches from the floor, rendering it possible for a person slipping or falling upon the path to be precipitated into the pit and upon -the revolving •fly wheel. Under the evidence the jury was justified in finding that this construction was defective, and constituted a breach of defendant’s duty to furnish the deceased a safe place to work. To an experienced engineer this defect might be revealed at a glance, but it does not follow that it would be so apparent to a boy of seventeen, just entering such employment, and we think it was properly submitted to the jury to say whether,, considering these circumstances and the time he had been in the service, he ought to have known and appreciated the peril' to which he was exposed by the defendant’s neglect. Shebeck v. Cracker Co., 120 Iowa, 414; Sachau v. Milner, 123 Iowa, 387; Mace v. Boedker, 127 Iowa, 721; Woolf v. Nauman, 128 Iowa, 261.
VI. Other points, made in behalf of the appellant, may be condensed in the proposition that the verdict is not sustained by the evidence. With this contention we can not agree. For reasons already stated we are satisfied that both upon this alleged failure of the defendant to furnish the deceased a reasonably safe place to work, and upon the question whether reasonable care was exer*699cised to properly instruct and warn him concerning the dangers to which he was exposed, there was -enough evidence to go to the jury. Upon the question of contributory negligence, the jury, under the rule discussed in the fourth paragraph of this opinion, were justified in finding that his death was not in any degree chargeable to his own want of reasonable care.
7. Same: proximate cause. But counsel say that, even if we concede the alleged negligence of defendant, there is no evidence from which we may trace any casual connection between such negligence and the death of the deceased. It is true, as already said, that no eyewitness was produced to testify to the particulars of the accident, and that the cause and manner of the death of the intestate must be drawn as inferences from the facts and circumstances developed on the trial. This, say counsel, leaves the cause of the accident a mere matter of speculation or surmise, -but such is not 'the case. More frequently than otherwise the truth or falsity of any disputed fact proposition is dependent, in greater or less degree, upon circumstantial evidence. It is of course not an infallible guide; neither, indeed, is the direct testimony of living witnesses, but human experience teaches us confidence in its general reliability. Its sufficiency in' determining the cause of any given accident is a matter of almost daily recognition by the courts. For example in Hopkins v. Knapp, supra, the defendant had left an open elevator shaft without proper protection. An employe being in the upper story of the building alone fell down the shaft and was killed. No one saw him fall, and the cause of the accident was wholly a matter of inference from the surrounding, circumstances. This we held to be sufficient to take the case to the jury. The same rule was applied in Dalton v. R. R. Co., 104 Iowa, 26. The late and thoroughly considered case of Huggard v. Refining Co., 132 Iowa, 725, is also in point. There an *700employe, while passing under an opening extending through the upper floors of the employer’s factory, received a blow upon the head, -striking him senseless. There was no other witness of the accident. He did hot see or know the source of his injury. Near him was found a piece of iron piping, which, btrt a short time before, had been seen on one of the upper floors near the opening, into which it could have rolled and- fallen upon the plaintiff, and this was the theory upon which the claim for damages was based. There, as in this case, it was contended that the proximate cause of the accident was not sufficiently established. While not disputing the soundness of the rule that to sustain a finding that defendant’s negligence was the proximate cause of the injury the case must present something more than a mere possibility or conjecture, this court said, “It is equally well established that the cause" of an accident may be inferred from circumstances,” and sustained a verdict for the plaintiff. While plaintiff can not recover upon a case which does no more than -show a possibility that the injury is chargeable to the defendant’s negligence, he is not bound to prove either the negligence or the proximate cause beyond a reasonable doubt. Such a rule would work an absolute denial of justice in a great majority of cases. Proximate cause is, under all ordinary circumstances, a question of fact; and, where it depends upon circumstances from which different minds might reasonably draw different conclusions, or where all the known facts point to the negligence of the defendant. as the cause, the submission of the question to the - jury affords no ground for assignment of error by such defendant-. 29 Cyc. 632.
Proof of proximate cause is subject to no more burdensome rule than is applied to the proof of any other essential fact in ¡an ordinary law action. It must be established by a preponderance of the evidence, direct or *701circumstantial. If there be shown any facts bearing upon the question, and they afford room for fair-minded men to conclude therefrom that one theory of the case is better supported than the other, the question can not be properly withdrawn from the jury. Schoepper v. Chemical Co., 113 Mich. 582 (71 N. W. 1081) ; Jucker v. R. R. Co., 52 Wis. 150 (8 N. W. 862). In our judgment the record before us presents a ease which would justify a jury in finding that the wheel pit was not properly guarded, that the opening left below the lower rail was such as to expose the deceased to the danger of slipping or falling from the cement path into the' pit and upon the wheel, and that the bruise upon the rail, the rope pulled from the shive into the pit from the east passageway, the blood spots, and the place where the body was thrown, are facts from which the jury could fairly find that he did thus fall, while attempting to make his way along said path. A cause being shown which might produce an accident, and it further appearing that an accident of that particular character did occur, it is a warrantable inference, in the absence of showing of other cause, that the one known was the operative agency in bringing about such result. Brownfield v. R. R. Co., 107 Iowa, 258; Settle v. R. R. Co., 127 Mo. 336 (30 S. W. 125, 48 Am. St. Rep. 633).
The fact that a horse is found lying upon a railroad right of way, in a wounded and mangled condition, justifies the inference that it was struck by a passing train. A fire starting in the dry grass or underbrush near a railway, immediately after a train -has passed, will support a finding that it was kindled by sparks or cinders from the locomotive. In the Settle case above cited proof that, a handhold on the car, from which -the deceased fell, and to which he had been clinging, was bent out of shape was held to be evidence that this imperfect appliance was the cause of the fall. If the plaintiff do *702no more than to show a state of facts which is equally consistent with the theory of due care on the part of the defendant, then of course he must fail. Neal v. R. R. Co., 129 Iowa, 5; Huggard v. Refining Co., 132 Iowa, 736; O'Conner v. R. R. Co., 129 Iowa, 636. But he is not bound to exclude the possibility that the accident might have happened in some other way, for that would be to require him to make his case beyond a reasonable doubt. He is only required to satisfy the jury, by a fair preponderance of the evidence, that the injury occurred in the manner he contends it did. Woodall v. R. R. Co., 192 Mass. 308 (78 N. E. 446) ; Stratton v. R. R. Co., 95 Ill. 25; Schoepper v. Chemical Co., 113 Mich. 582 (71 N. W. 1081) ; Tholen v. R. R. Co., 10 Misc. Rep. 2,83 (30 N. Y. Supp. 1081); Drennen v. Smith, 115 Ala. 396 (22 South. 442); Whitney v. Clifford, 57 Wis. 156 (14 N. W. 927) ; Whitcher v. R. R., 70 N. H. 242 (46 Atl. 740); Kerwin v. Collar Mills, 28 Out. Rep. 73, affirmed in 25 Out. App. Rep. 36. The question is not what the trial court or this court would infer from a given state of facts, but whether the jury, as reasonable and intelligent men, might legitimately conclude from the proofs offered that the accident occurred in the manner alleged by the plaintiff. Mumma v. R. R. Co., 73 N. J. Law, 653 (65 Atl. 210). The finding of the jury in this case that defendant was negligent as charged, and that such negligence was the proximate cause of the injury to the deceased, and that he did not contribute to such injury by his own want of care, is not without due support in the evidence, under the rules of law to which we have adverted, and the district court did not err in refusing to set it aside.
The judgment appealed from is' therefore affirmed.