In Claris v. Oregon Short Line R.R. Co., 56 Idaho 169, 51 P.2d 217 (1935), the plaintiff was a machinist employed to grease the engine bushings for a railroad company. As a practical joke, the plaintiff's supervisor and a fellow employee loaded the plaintiff's grease gun with water. The supervisor handed the grease gun to the plaintiff and directed him to go ahead and use it. The grease gun discharged water, grease, metal shavings and borings into the plaintiff's face causing him to lose his left eye. The Court held that the railroad company could be held liable for the supervisor's act, explaining: "The true test in all cases by which it may be determined whether the negligent act causing the injury is chargeable to the master or is the act of a co-servant is, was the offending employee in the performance of the master's duty in reference to the particular act causing the injury, an act done in the performance of a duty that the master owed his servant? If so, his negligence is that of the master, and liability follows." Applying the test so adopted by this court, it is clear that in supplying the respondent with the grease gun in question, and in informing respondent that the grease gun was ready and thereafter directing respondent to go ahead and use it, the supervisor was performing a duty which his master, the appellant, owed the respondent, and that the supervisor was guilty of an act of omission, imputable to appellant, in the performance of that duty by failing to supply the respondent with a safe tool with which to grease the bushing. (Id. at 174, 51 P.2d at 218.)