The plaintiff had worked upon the machine two days and a half before the accident. He knew that the iron apron which caught his fingers would spring back if pulled down and released. He knew its position relatively to the front opening, between the edge of which and the apron his fingers were caught. Knowing these facts, he knew that, if he put his hand through the opening and let the flap spring up while it was there, it would get pinched. He also knew by experience the degree of force necessary to hold the apron down. We do not see what the defendant could have told the plaintiff that he did not know before, if he possessed the ordinary intelligence of boys of fifteen. Ciriach v. Merchants’ Woolen Co. 146 Mass. 182. Probert v. Phipps, 149 Mass. 258.

.Exceptions sustained.