The plaintiff knew that horse cars would come along every few minutes and be pushed over the trench by individuals. It was not expected that his work should stop whenever a car passed, nor that the cars should stop passing there. The suggested negligence on the part of the defendants is that they did not station a watchman there to prevent volunteers from helping to push cars over the trench. It seems to us, however, that the injury to the plaintiff must be deemed to have resulted from a pure accident, and that the omission to guard against it was not negligence on the part of the defendants.

The evidence of what was usually done at other places and under different circumstances was rightly excluded. Bailey v. New Haven & Northampton Co. 107 Mass. 496. Hinckley v. Barnstable, 109 Mass. 126. Exceptions overruled.