Negligence, Employer's liability. One, who is employed in a well lighted spinning mill and knows that, in dipping liquid soap from a tank into a trough where combed wool is washed, a fellow employee sometimes drops some of the soap upon the floor, and who in the course of his duties walks upon that part of the floor and is injured by slipping upon some soap which the fellow employee had dropped there and should have cleaned up, cannot recover from his employer although he did not know and had not been told what was the effect as to slipperiness of liquid soap upon the floor, the risk being an obvious one which he had assumed, and the accident being due to the carelessness of a fellow servant.