Dodge, J.
1. The first assignment of error involves, primarily, the assertion that there was no credible evidence upon which the jury might have reached their conclusions expressed in the special verdict. With- this we cannot agree. While on many of these questions -there was substantial conflict and, perhaps, what we might deem a preponderance of evidence to the contrary, there was at least some evidence in support of each of the answers, except perhaps the third, which, however, is immaterial in presence of the finding of defendant’s actual knowledge of the defect in the wrench.
2. It is strenuously urged that a monkey wrench falls within the category of common and simple tools, as to which,, it is asserted by the appellant, the master is not bound by the ordinary rule that he must supply his employee with suitable and safe appliances. It may be conceded that, generally speaking, a monkey wrench is in such category, and the rule *322of law is well established in this state and elsewhere that in case of snch simple tools no liability rests on the master for the ordinary perils resulting from their use., nor for those latent and usual defects or weaknesses which, by reason of the common, usual character of the appliance, are presumed to be known to all men alike. This exemption from liability is, we believe, in all cases based upon the condition that the defect and peril are such that no superiority of knowledge in the master over the employee exists or can be presumed. Corcoran v. Milwaukee G. L. Co. 81 Wis. 191, 51 N. W. 328; Borden v. Daisy R. M. Co. 98 Wis. 407, 74 N. W. 91; Olson v. Doherty L. Co. 102 Wis. 264, 271, 78 N. W. 572; Marsh v. Chickering, 101 N. T. 396, 5 N. E. 56; Cahill v. Hilton, 106 N. Y. 512, 518, 13 N. E. 339; Garnett v. Phoenix B. Co. 98 Fed. 192; Louisville, E. & St. L. C. R. Co. v. Allen, 47 Ill. App. 465; Georgia R. & B. Co. v. Nelms, 83 Ga. 70, 9 S. E. 1049. Another qualification of the master’s 'liability indulged in case. of such simple tools and appliances is exemption from a duty to inspect to ascertain the development of defects or disrepair in the course of their use, based also upon the assumption that such conditions are as much within the observation of the employees as of the master, if not more so. Twombly v. Consolidated E. L. Co. 98 Me. 353, 57 Atl. 85; Wachsmuth v. Shaw E. C. Co. 118 Mich. 275, 76 N. W. 497; Cregan v. Marston, 126 N. Y. 568, 27 N. E. 952; Relyea v. Tomahawk P. & P. Co. 110 Wis. 307, 85 N. W. 960. While these rules result practically in a relaxation of the mastei-’s duty and liability in the case of such simple tools, they are not at all in denial of the general underlying principle of the law of negligence that one who -knowingly exposes another to a likelihood of injury is liable therefor, in the absence of consent by such other or of contributory negligence. As stated above, the relaxation of the master’s duty and liability rests on the assumed equality of knowledge and ability to discover the defect complained of. It can have no application to a defect of which the master is *323actually cognizant, and which, as a reasonable man, he should appreciate is likely to result in injury to one using the implement as it is likely to be used, and which is' neither known to the employee nor of such a character as to be obvious to that ■observation which may be expected to accompany its use. In such case the general rule of negligence as above stated is fully effective, and the master who knowingly and negligently •exposes his employee to a peril unknown to the latter must respond for the damage which results. Vant Hul v. Great Northern R. Co. 90 Minn. 329, 96 N. W. 789; Johnson v. Mo. Pac. R. Co. 96 Mo. 340, 9 S. W. 790; Chicago, K. & W. R. Co. v. Blevins, 46 Kan. 370, 26 Pac. 687; Twombly v. Consolidated E. L. Co., supra. In the case before us there was at least some evidence that the screw intended to move and hold the jaws of this wrench was so defective that it would not accomplish the latter purpose under pressure; that such fact was brought to the actual notice of the defendant’s representative a week or ten days before; that it was not such as to be obvious to one attempting to use the wrench; that the wrench was expected to be used, as in this particular case, in tightening or loosening nuts upon running machinery with exposed gears, from all of which the jury might have considered it within the realm of ordinary expectation that, when so used, the jaws would be likely to part, allow the wrench to slip, and the hand of the operator to come in contact with moving parts of the machinery to his hurt. Hence we cannot say that as a matter of law there was no evidence to support liability for an injury so occurring.
3. The chief difficulty arises upon the appellant’s contention that there is no finding that the defect in the wrench was the proximate cau.se of the plaintiff’s injury. It should be remembered that the injury resulted directly from contact with an uncovered gearing, the presence of which was not only unlawful under sec. 1636y, Stats. 1898, and therefore negligent, but might also have been considered negligence on the part of *324tbe defendant independently of sncb statute. In tbis situation tbe court submitted to tbe jury no question as to wbetber tbe defects in tbe wrench and absence of warning to tbe plaintiff were tbe proximate cause, but wbetber there was “any want of ordinary care on tbe part of tbe defendant which proximately caused tbe plaintiff’s injury.” Tbis tbe jury answered “Yes.” There was no instruction that they could so answer only in case they found tbe defect in tbe wrench to have been tbe natural and probable cause of the injury, but, on tbe contrary, they were instructed to answer affirmatively in case they so found, and, by separate and independent paragraph, also to answer “Yes” if they found there was any negligence on defendant’s part which was tbe natural and probable cause. We think tbe conclusion irresistible that tbe jury might well have believed that tbe exposed gearing was an act of negligence on tbe part of defendant, and that- it was tbe proximate cause within tbe definition given by tbe court. If so, eon-cededly tbe defendant would not be liable, for tbe plaintiff bad full knowledge of tbe exposure of tbis gearing, and bad, doubtless, assumed any risk therefrom.
It is suggested that proximate causation of tbe injury by tbe defect in tbe wrench is so obvious that tbe court must declare it as matter of law. Tbe legal proximate relation between cause and result involves so much of inference from tbe known characteristics of human nature, in deciding what is or should be within tbe reasonable anticipation of tbe ordinarily prudent and intelligent person under all tbe circumstances, that very rarely can that relationship be declared, at least in tbe affirmative, as matter of law. Doubtless there may be sucb cases, as where a railroad train breaks through a known defective bridge, or a pedestrian on a sidewalk steps into an obviously dangerous bole, or a surgical operation is-negligently performed. Allen v. Voje, 114 Wis. 1, 17, 89 N. W. 924. In tbis case, however, while tbe actual causal relation is perhaps undisputed, we think it cannot be said as mat*325ter of law, although it might well be found as a fact, that one supplying such a defective wrench should, as an ordinarily prudent and intelligent man, anticipate the likelihood that it would be used in such a way as to cause injury. Jíe are persuaded that was the question for the jury and has not been passed upon by this verdict, which therefore does not support the judgment for the plaintiff.
By ihe Gourb. — Judgment reversed, and cause remanded for new trial.