Principle: A Master is liable to third persons for every such wrong of his servant as committed in the course of service. For acts committed beyond the scope of employment, the master is liable only if he has expressly authorized the act. A owned a bus and he had hired B to drive it and C to be the conductor. One day, when B had stepped out of the bus to have a cup of coffee. C decided to turn the bus around so that it was ready for its next trip. While doing so, C ran over D's leg, causing major injuries to him. D sued A for damages.