hose 48 near its end and includes an electrical switch 62 for adjusting the air flow in the spreader 20 as seen in fig4 the switch 62 is electrically connected to an electrically actuated valve 64 which is coupled to the entrance conduit 24 the switch 62 is capable of being placed in at least two positions in the illustrated embodiment of the invention the electrically actuated valve 64 is in the form of a solenoid valve which can either completely open or close the entrance conduit 24 either permitting or restricting the movement of air to the metering block 22 in an alternative embodiment of the invention the electrically actuated valve can have three or more positions such that when the position of the switch 62 is adjusted a signal is sent to the electrically actuated valve 64 which in turn adjusts its position to either permit more or less air to pass through the entrance conduit 24 the switch 62 selectively connects the electrically actuated valve 64 to a battery 68 in a preferred embodiment of the invention the battery 68 is capable of producing a current of about three amperes at twelve volts dc the air flow to the metering block 22 can also be manually controlled by adjusting a ball valve 25 fig2 and 4 located along the pressurized gas entrance conduit 24 in one embodiment of the invention the ball valve 25 acts as an emergency shut off for the spreader 20 the operation of the spreader is as follows the engine 44 is used to power the compressor 38 the compressor 38 works to compress the air inside the.