GAUGING APPARATUS FOR MEASURING AND REMOTE INDICATION OF THE WEIGHT OF LIQUID IN A TANK OR TANKS, BY PNEUMATIC MEANS, AND COMPUTING AND DISPLAYING SPECIFIC GRAVITY, LEVEL OF LIQUID INTERFACE BETWEEN TWO IMMISCIBLE LIQUIDS OF DIFFERING SPECIFIC GRAVITY BY MEANS OF SENSORS, VALVES, TRANSMISSION LINES, SWITCHES, PNEUMATIC COMPUTING RELAYS AND GAUGES