The purpose of this investigation was to determine if there was a relationship between the quantity of inhibitor known to diminish the corrosion rate and the potential of a cathodic surface. The potential required to keep a constant current of one milliampere flowing from cathodic corrosion specimens through dilute acid solutions to which one or more known or commercial inhibitors had been added was measured against a saturated calomel reference electrode. Platinum, mild steel, copper, monel, inconel, yellow brass, nickel and tin were used as cathodic specimen electrodes. Platinum was also used as the anode. Four point nine per cent sulfuric acid, five per cent acetic acid and five per cent phosphoric acid were used as electrolytes. / Master of Science