Tbe defendant made a motion for nonsuit at tbe close of tbe plaintiffs evidence, and it now claims that, regardless of any question of error in tbe reception of evidence or charge of tbe court, tbe judgment should be affirmed because tbe plaintiff made no case. Defendant’s contentions on this point 'are, in general, that no negligence was shown-on its part, and that, even conceding that there was any such negligence shown, tbe plaintiff knew, or ought to have known, of the danger, and assumed the risk. Tbe plaintiff claimed negligence in two respects: (1) In not providing tbe machine with a guard, and (2) in not warning tbe plaintiff of the danger resulting from sharp slivers of brass wbicb occasionally occurred on tbe sides of tbe sheets. As to tbe first of these claims there was evidence showing that a sort of a metal canopy or guard was sometimes placed over tbe top-rollers wbicb came down in front nearly to tbe sheet of brass, that this canopy was not on the machine at the time of tbe accident, and tbe claim is that its absence constituted negligence. The evidence, however, failed to show that this canopy or guard was in general use in this shop or other shops upon similar machines; that its principal object was to prevent foreign siib stances from falling on the sheet of brass as it was-passing through tbe rolls, nor was it made apparent bow it could in any way have prevented tbe accident in question. On these grounds the court rightly struck out the evidence as= to tbe guard and eliminated that question from tbe case.
Upon the question of failure to warn, however, we think *279there was evidence from which the jury might find negligence on the part of the defendant, and we do not think that the evidence showed assumption of risk as matter of law. The evidence tended to show that while the edges of the sheets were frequently rough and uneven, and the plaintiff knew that fact, it was only occasionally, sometimes at intervals of several days, that a sharp sliver formed longitudinally on the edge, and that the plaintiff had no knowledge that such slivers ever formed. Now it is manifest that the danger to an operative resulting from the occasional presence of these sharp rigid slivers was entirely different from the danger resulting from the presence of a mere rough edge, and if this occasional and serious danger was known, or under the circumstances ought to have been known, to the employer, and was not known or capable of being discovered by the employee in the exercise of ordinary care, the employer would be guilty of negligence in not warning the employee thereof when setting him at work. By parity of reasoning, the plaintiff could not properly be held to have assumed the risk as matter of law, so we conclude that the motion for a nonsuit was properly overruled.
The serious questions in the case arise upon the charge of the court and the special verdict. The court charged the jury on the subject of burden of proof and preponderance of the evidence as follows:
“I shall use the term ‘burden of proof’ in connection with these instructions, and by burden of proof I mean that it is incumbent on the party affirmatively asserting an allegation to establish it by a fair preponderance of the credible evidence, facts, and circumstances proven on the trial. And by ‘preponderance of evidence,’ as I have used the term, is meant the greater convincing power of evidence. That is, in- the trial of a lawsuit that side has furnished the preponderance of evidence which has produced evidence of greater convincing power in the minds of the jury than that produced by the other side. And when the law imposes upon a party the burden of proof it means that such party is bound to produce evidence in support of the proposition involved of greater con-*280vineing power than that produced by the other side. Such convincing power of evidence is not necessarily determined by the number of witnesses, for it may be that the testimony given by one witness has greater convincing power than that given by several witnesses contradicting or tending to contradict that given by the one.”
The definition thus given of the term “preponderance of the evidence” was substantially correct, but not so with the definition of “burden of proof.” It is well settled by a long series of decisions in this court that the party upon whom rests the burden of proof does not lift that burden by merely producing a preponderance of evidence. He may produce a preponderance, that is, he may produce evidence of slightly greater convincing power to the mind than that produced by his opponent, but still his evidence may be weak and leave the mind in doubt. In order to entitle himself to a finding in his favor his evidence must not only be of greater convincing power, but it must be such as to satisfy or convince the minds of the jury of the truth of his contention. This idea, in some definite and certain form, must be given to the jury or the instruction will be incomplete and erroneous. Gores v. Graff, 77 Wis. 174, 46 N. W. 48; Pelitier v. C., St. P., M. & O. R. Co. 88 Wis. 521, 60 N. W. 250; Guinard v. Knapp-Stout & Co. Co. 95 Wis. 482, 70 N. W. 671; Curran v. A. H. Stange Co. 98 Wis. 598, 74 N. W. 377; Knopke v. Germantown F. M. Ins. Co. 99 Wis. 289, 74 N. W. 795; Ward v. C., M. & St. P. R. Co. 102 Wis. 215, 78 N. W. 442; Bowe v. Gage, ante, p. 245, 106 N. W. 1074. This idea was nowhere given to the jury in-the charge before us, and the omission was fatal.
. The court defined ordinary care in connection with the seventh question as “such care as boys of the age, intelligence, and experience of the plaintiff usually exercise under similar circumstances.” This instruction is complained of as erroneous because it does not carry the idea that the care used must *281be tbe care ordinarily used by tbe great mass of boys or by tbe class of ordinarily careful boys. Tbe instruction would have been more exact bad it contained some words of tbis import, but under tbe decisions of tbis court we think it must be beld tbat it fairly contains tbat idea, and bence is not erroneous. Coppins v. Jefferson, 126 Wis. 578, 105 N. W. 1078; Pumorlo v. Merrill, 125 Wis. 102, 103 N. W. 464.
Tbe court gave tbe following general instruction:
“You are further instructed tbat tbe danger incident to tbe feeding of tbe straightening rolls of tbe machine, considered apart from tbe added dangers, if any, arising from tbe presence of tbe rough edges or slivers on tbe bars of brass, were open and obvious and are presumed to have been comprehended by tbe plaintiff, and in respect to whifeh be assumed all risks.”
Tbis instruction, while doubtless correct as a general proposition, bad no legitimate bearing on any question of tbe special verdict except tbe seventh, nor would it have any bearing on tbe seventh question which would be obvious to tbe jury unless it were explained to them tbat assumption of risk was a form of contributory negligence or want of ordinary care. No such explanation was made and tbe instruction seems therefore to have been misleading rather than helpful.
Passing to a consideration of tbe verdict, we tbink it must be said tbat it is not happily framed. After tbe elimination of tbe question of tbe lack of tbe guard from tbe case tbe issues were simple and may be-stated as follows: (1) Was tbe plaintiff set at work at tbe machine by tbe defendant? (2) Was tbe defendant guilty of negligence in failing to warn tbe plaintiff of tbe danger resulting from tbe occasional presence of slivers ? (3) If so, was such failure to warn tbe proximate cause of tbe accident? (4) Did tbe plaintiff assume tbe risk or was be guilty of contributory negligence ? In tbis statement of tbe issues it is not intended to indicate tbat .the issues should be submitted to tbe jury in tbis form, but *282simply that these were the ultimate issues to be covered by the questions of the verdict. Turning to the verdict, it is at once seen that the second question relates rather to an eviden-tiary matter than to one of the material issues. The issue was whether the plaintiff did his work with ordinary care; the question whether he did it as other men did was eviden-tiary only.
The third question asks the jury whether the plaintiff' knew that there were liable to be slivers and rough edges on the bars of brass. The coupling of these two elements together in the question was prejudicial to the plaintiff in a high degree. He admitted that he knew of the rough edges, but denied that he knew of the liability of thei*e being slivers on the edge. Here was really the crux of the case. If he knew that slivers were liable to come at any time, it is difficult to see how it could be said that he did not assiune the risk, and yet the two matters were coupled together in the question as-if they were identical, so that the jury could not, by a single categorical answer, separate them.
Again, the verdict on its face is inconsistent. ’ By their answers to questions 3 and 4 the jury found that the plaintiff' knew that there were liable to be slivers on the bars and ought to have known of the danger of his glove or hand being caught on them. If these were the facts, he undoubtedly assumed the risk of the danger. On the other hand, the jury found by their answer to question 1 that he was not guilty of any want of ordinary care which contributed to the injury. Assumption of risk is held by this court to be a form of contributory negligence, and in the absence of any instruction limiting the-scope of the question (and there was none in this case), a general finding of absence of contributory negligence includes the assumption of risk as well. So the verdict by necessary construction finds both ways on the question of assumption of' risk. It is quite difficult also to see how the answers to questions 4 and 5 can be reasonably reconciled. The findings are-*283that plaintiff ought to have known that there was clanger of' his hand or glove being caught, but that the defendant' ought not to have known that there was danger of the plaintiff’s hand’ being drawn into the rolls as it was. Just why the plaintiff,, a boy of sixteen, should be charged with knowledge of the danger that his hand might be caught, and the employer should' not'be-charged with knowledge of the danger of the plaintiff’s-hand being drawn into the rolls, is not very apparent.
There are a large number of rulings upon evidence which are complained of. We shall not undertake to review them in detail. The plaintiff attempted to show by various questions-asked of experts that the machine was a dangerous machine,, or that it was so regarded, or that boys were not usually set at work upon it for that reason, and evidence of this character-was excluded. The rulings upon this class of evidence were correct. The question whether the work was so dangerous as-to require the giving of a warning was a question to be solved' by the jury from the facts and circumstances in evidence. It was not a subject on which the opinion of experts was admissible. Olwell v. Skobis, 126 Wis. 308, 105 N. W. 771. In this connection attention is called to_ a ruling upon evidence adverse to the defendant, which of course is not here for-review but which will probably arise upon another trial, and hence may be- properly referred to in order to avoid error on-such new trial. The plaintiff took the testimony of Schmelling, the foreman, under sec. 4096, Stats. 1898, before trial,, and was allowed, against objection, to introduce and read the same upon the trial, although Schmelling was present and was afterwards examined as a witness. Schmelling was not an officer of the defendant-, but simply an employee. This court has held such depositions inadmissible when the employee is present in court. Hughes v. C., St. P., M. & O. R. Co. 122 Wis. 258, 99 N. W. 897.
By the Court. — Judgment reversed, and action remanded' for a new trial.