Combination animal leash and umbrella includes a center post with a closeable umbrella cover that fits convexly over the leash attached to the inside of the umbrella. The players navigate the course by hitting a ball with a bat over, through or around the objects while avoiding the obstacles. a spray for achieving an effective heat exchange, and out of regard for the effectiveness it is necessary for a continuous deaeration of the water to be carried out, which is effected by the sucking of air direct from the condenser, possibly supplemented with an external NCG condenser or by leading the supply water through a pre-deaerator under vacuum. The liquid fuel may be applied as a film through one or more orifices or a porous wall material, or may be applied by spraying the fuel on a surface within the chamber. A surface magnetic flux density of the permanent magnet facing the stator core is lower at an end portion than at a central portion of the permanent magnet in the direction of thrust of the rotary shaft. Instead, simple tilting type mercury switches are used for sensing the acceleration of a vehicle.