Opinion by

In the business of manufacturing structural iron and steel, *175conducted by the defendant as a receiver, use was made of a large stationary riveting machine driven by compressed air. The pieces of iron and steel to be riveted were held in place by bolts which passed through them, and were swung from a traveling crane which moved on girders above the machine and carried the pieces between its jaws. In each jaw there was set a cylindrical piece of steel oh which there was a hollow or cup, the size and shape of the head of a rivet. One of the cups was fixed, the other was movable, and its position was changed by the use of a lever. The hot rivets inserted in the holes in the pieces were brought successively in a position where one end of a rivet would fit into the immovable cup. The other cup was then driven forward by turning on the compressed air with such force as to head the rivet. When rivets had been placed in all the holes except those occupied by the temporary bolts, the pieces were carried forward a few inches and the bolts were removed. The pieces were then swung back between the jaws of the machine, rivets placed in the empty holes, and the work of riveting was completed. A number of men were employed about the machine in handling the structural iron, heating and inserting the rivets and adjusting them to the cups, and in removing the temporary bolts.

On the first day of his employment in the shop the plaintiff was directed to remove the bolts. In doing this he stood a foot and a half from the machine and loosened the nuts with a wrench and took out the bolts with his hands. He had been engaged at this work only a few hours when the pieces from which he was removing a bolt swung back between the jaws of the machine, his glove caught on a nut and his hand was carried back between the cups. At the same instant the machine started in motion, the cups closed and his hand was crushed between them.

What caused the machine to start no one seemed to know. The operator was some distance from it and no one touched it at the time. Witnesses, some of whom operated the machine and others of whom had worked about it, testified that frequently it started automatically and that it had done this from the time it was first placed in the works five or six years before, and that this was generally known in the shop. What caused the automatic starting of the machine was not shown *176further than that it was probably due to the variation of air pressure on the valves. It was shown that the self-action was not due to a condition brought about by wear and tear but that it was an inherent tendency, resulting from the machine’s construction. The danger then to which the plaintiff was exposed was not one ordinarily incident to his employment nor obvious to him. No one would anticipate the sudden starting in motion of such a machine because of some peculiarity of its construction. When it was at rest and no one was near it to start it by accident or design, it was apparently as harmless as any other inanimate and quiescent object, and the plaintiff might assume he was safe in standing close to it where his work required him to be. The danger was a hidden one, of the existence of which it might be inferred that his employer knew or should have known. Against such a danger there was a duty to warn him.

The case was clearly one for the jury and it was submitted in a manner that carefully and fully guarded the defendant’s rights.

The judgment is affirmed.