The plaintiff was permitted to go to the jury on two counts under the employers’ liability act, (St. 1887, c. 270,) one alleging an injury by reason of a defe, in *138the ways, works, or machinery of the defendant, and the other an injury received by reason of the negligence of a person in the service of the employer intrusted with and exercising superintendence, whose sole or principal duty was that of superintendence. In regard to each count, the defendant asked for a ruling that there was no evidence to support it; and the principal exceptions arise from the refusal of the presiding justice to give either of these rulings.
The plaintiff was injured by the fall of a staging on which he was working. This staging was erected by the side of a wood pile for the purpose of enabling the workmen to pile the wood higher. It was about fifteen feet high, twenty feet long, and five feet wide, and it was taken down and put up from time to time in different places, and was intended to be used from four days to a week at a time in each place where it was erected. We think it was competent for the jury to find that the staging when erected was a part of the defendant’s ways, works, or machinery.
Was there evidence that it was defective? It was held in place by three triangles or brackets, which were put up and taken down as a part of the staging, each of which was fastened to the wood pile by six wooden cleats, one end of each cleat being fastened into the end of one or more sticks of wood in the wood pile, and the other end to an upright part of the bracket. There were three nails at each end of each cleat, and the cleats were about a foot and a half or two feet long, about two inches wide, and about an inch thick. There was one prop or support under the outer edge of one end of the staging when it fell. The staging was designed to hold a quantity of wood, which was to be brought there in carts and thrown upon it from the ground, and also two men, who were expected to get upon it and throw the wood upon the pile. It was constructed in such a way that a load upon it would have a great tendency to draw out the cleats from the pile to which they were fastened, and it was a question of fact for the jury whether it was safely and properly constructed in reference to the use for which it was intended. The judge rightly refused to rule that there was no evidence for the jury under this count. There was evidence that this staging was erected, and that the work of piling the wood was going *139on under the superintendence of one Campbell, and we are of opinion that the jury were well warranted in finding that his principal duty was that of superintendence. There was also evidence from which they might infer that he was negligent, either in not seeing that the staging was properly constructed, or in permitting it to be overloaded. The fact that it fell in the manner and under the circumstances described is proper for consideration, as tending to show that he was negligent. Arkerson v. Dennison, 117 Mass. 407, 411. There was evidence that he ordered or permitted a whole cart load of wood to be put upon the staging at the time the plaintiff was injured, when it had been the custom to put but half a load on at one time.
It did not appear that the plaintiff understood and appreciated the danger of injury from working on the staging so far that he can be said to have assumed the risk. Fitzgerald v. Connecticut River Paper Co. 155 Mass. 155. Mahoney v. Dore, 155 Mass. 513. We are of opinion that this count of the declaration was rightly submitted to the jury.
The only other exception was to the admission of the testimony of Ellsworth, the engineer. We are of opinion that a person who has made a special study of the strength of materials and the proper mode of building structures to sustain weight may be allowed to give his opinion as to whether a staging erected in a specified way can safely be trusted to carry a particular load. That was the substance of the question put in this case. Although, by reason of its form, it did not direct the attention of the witness to the elements of fact involved so particularly as it might have done, it was not so objectionable as to be incompetent. Poole v. Dean, 152 Mass. 589.
It is apparent that the witness was found by the court to be a competent expert. What the evidence was on which this finding was made does not appear beyond the fact that he was an engineer. If the defendant desired us to revise the presiding justice’s finding of fact on this point, he should have inserted in his bill of exceptions all the material evidence bearing upon it. The question whether the witness was an expert is not open. Campbell v. Russell, 139 Mass. 278. Perkins v. Stickney, 132 Mass. 217.
Fxceptions overruled.