The board, affirming the decision of the single member, found that the employee received an injury in the course of and arising out of his employment. This finding must stand provided there is evidence in its support. Pass’s Case, 232 Mass. 515. Chisholm’s Case, 238 Mass. 412, 419. Walker’s Case, 243 Mass. 224, 225. The burden of proof rests upon the employee to establish his claim by a fair preponderance of evidence. Sponatski’s Case, 220 Mass. 526. The testimony need not be narrated. It was sufficient, with the rational inferences susceptible of being drawn therefrom, to warrant a finding that a belt flew off a pulley and struck the employee with such force as to cause, either by the impact or his consequent fall, a fracture of his skull. Although there was no eye-witness of the accident, the conclusion of the board is justified. There were specific physical facts affording a definite conception of the way in which the injury to the employee occurred. The case at bar is distinguishable from Sanderson’s Case, 224 Mass. 558, Dube’s Case, 226 Mass. 591, Foster’s Case, 242 Mass. 386, 388, and similar authorities.

Decree affirmed.