The plaintiff was employed by the defendant as a machinist’s helper in the construction of the battleship North Dakota. Just before the accident he had been at work in the fire-room, standing on a platform that was about eighteen feet above the floor of the room. He testified that, after his job was completed, he started to step from the platform to a staging near by, in order to return to the deck above, when the light in the fire-room went out, leaving him in total darkness. He missed his footing, and fell to the floor, sustaining the injuries for which he sues.
The electricity for the lights was generated on the defendant’s premises, at a distance from the dock where the ship was lying, and was conducted from the power house by a main circuit, and thence by three sub-circuits to the various parts of the ship. There were minor sub-circuits or mains, and the incandescent *45and arc lights were not on the same circuit. The wires were covered with a tough insulating fibre composed of hemp and rubber. Although the evidence was conflicting, it could be found that on the day of the accident, March 18, 1909, the fire-room, in which the plaintiff was working, was lighted only by one large enclosed arc light; that during the week preceding the accident at different times this light was seen to flicker for a few seconds, “going out and coming in again,” and that at the time of the accident it was out for about fifteen minutes, — during which time the lights in the engine room and other parts of the ship remained burning.
The going out of. the arc light might be due to one of various causes, some of which would not be attributable to negligence on the part of the defendant. An expert called by the defendant testified that, if the arc light remained out for ten minutes, this would be caused either by the wire to the light being broken, the opening of switches, the blowing out of a fuse or by something defective in the lamp itself. On the evidence, including the expert testimony, the jury would be warranted in eliminating some of the possible causes, such as the cutting of the wires, the opening of a switch immediately before the accident and an overload at the power house, — which last would have put out all the lights on the ship. The plaintiff’s electrical expert, when questioned by the court, testified that he could not attribute the flickering in the week preceding as described to anything but a defective condition of the wiring, or a defective condition of the lamp itself. He was of opinion that the flickering of the light, and later its going out, was due to the gradual wearing of the insulation of the wires against the beams; and that, before the wires became worn enough “ to really put the light out,” an occasional contact with the beam would cause the flickering described. He testified that if the lamp flickered as described, and it was certain that there were no cross circuits, the trouble would be in the lamp itself. He further said that the defective insulation, which in his opinion caused the light to go out, probably existed at least since the flickering of the lamp five or six days before the accident, and would have been revealed by an inspection of the wires, which were in plain sight, nr by a test with instruments. If the trouble were in the lamp, *46and there was no short circuit, he said it would have existed probably a month. There was no evidence as to when this lamp and wire were installed, or as to any inspection of them.
In view of the foregoing, we are of opinion that there was evidence which, if believed, warranted the jury in finding that the light went out owing to a defect in the apparatus, which the defendant might have discovered and remedied by the exercise of reasonable care. And the plaintiff was not confined by his pleadings or by the evidence to a defective condition of the wires, but he could recover if the jury found that the defect was in the lamp. The question of the plaintiff’s due care clearly was for the jury. The rulings requested by the defendant were rightly refused. Saures v. Stevens Manuf. Co. 196 Mass. 543. Mehan v. Lowell Electric Light Corp. 192 Mass. 53. James v. Boston Elevated, Railway, 204 Mass. 158. Hopperman v. Fore River Ship Building Co. 214 Mass. 33.
The objection raised to the hypothetical questions put to the plaintiff’s electrical expert, that they were not the subject of expert testimony and were based on inadequate hypotheses, is untenable. The facts assumed in the questions might have been found by the jury. The questions were not inadequate in failing to assume the presence of incandescent lights, as there was evidence to sustain the plaintiff’s contention that there were no incandescent lights in the fire-room on the day of the accident. Greene v. Boston Elevated Railway, 207 Mass. 467. The other exceptions to evidence are not argued, and we treat them as waived.
Exceptions overruled.