The instructions given by the court covered the rulings asked for by the defendant, and stated the law correctly. Whether the defendant was or was not liable was matter of proof. The burden was on the plaintiff. If he failed for any reason to sustain it, the defendant was entitled to a verdict, not because prima faoie it appeared that there had been no neglect on his part, but because the plaintiff had not shown any. So far as any presumption existed, it was that the defendant performed its duty, as the court told the jury. The jury were also told in effect that under the circumstances of this case the breaking of the machinery was no evidence of neglect on the part of the defendant; which was going further than to say, as the defendant asked the court to rule, that the defendant was not bound to explain the cause of the accident.
We think, however, that the question to the witness Cumnock should have been admitted.
One of the issues at the trial was whether the defendant had properly inspected the shaft. The defendant introduced testimony tending to show that it had done so before the shaft was started, and from day to day while it was running. The witnesses testified, amongst other things, that the shaft ran without vibration, and that standing on the floor they could see if it or the pulleys oscillated an eighth of an inch. As bearing further on the sufficiency of the inspection made by the defendant, it called the witness Cumnock, who had had a long experience in dealing with machinery of that kind, and who was admitted to be an expert. The defendant’s counsel asked him the following question: “ Can you state whether or not an experienced person, looking at a shaft revolving, and pulleys upon that shaft revolving two hundred and fifty revolutions a minute, whether a person can see whether it ran true or not ? ” This was objected *311to and excluded, and the defendant’s counsel asked the further question, “ Whether a person standing upon the floor, an experienced person standing upon the floor and watching this, can see any oscillation?” and this also was excluded. It does not appear very clearly what the answer would have been, but it is fairly to be inferred we think that it would have been to the effect that any oscillation could have been seen by an experienced person in that position; and, assuming that the first question was objectionable in point of form, we think that the last should have been admitted. The subject was not one within the common experience of men. The jury could not tell whether an oscillation in a shaft of the size of this and as far above the floor, and with two heavy pulleys on it revolving at the rate of two hundred and fifty revolutions a minute, could be seen by an experienced person from the floor. Only a person of skill in the business, or familiar with the running of such machinery, would know. New England Glass Co. v. Lovell, 7 Cush. 319. Curtis v. Gano, 26 N. Y. 426. See Rogers, Expert Test. (2d ed.) § 109 et seq., for collection of cases. The question did not come fairly within the cases in which it has been held that the extent to which testimony may be accumulated, or allowed in rebuttal, is within the discretion of the court. Cushing v. Billings, 2 Cush. 158. Ashworth v. Kittridge, 12 Cush. 193. York v. Pease, 2 Gray, 282.
As to the question put to the witness Pepper, it is not necessary for us to consider now whether it was admissible at the stage of the examination at which it was put, even if it would have been admissible earlier, upon which we express no opinion. As there must be a new trial on account of the exclusion of the • question to the witness Cumnock, the question whether the interrogatory to Pepper was admissible .may become immaterial, or may arise under different circumstances.
Exceptions sustained.