This was a sign used on meters associated with loading racks at bulk plants. Plant operators were told that meters were calibrated specifically for gasoline products or distillate products (kerosene, heating oil, diesel fuel) and were not to be interchanged or accuracy would potentially be compromised.
In reality, many plants were operated by commission agents who were paid a commission on gasoline products sold through the plants, but for "chain store" tax purposes were technically "independent" agents on distillate products. Although it was strongly discouraged that agents did not exercise their independence and buy heating oil on the open market, the arrangement made it such that Standard Oil could not legally prevent such an agent from buying competitive products on the open market and using the equipment (which the operator was leasing) for storing and dispensing the distillate products. Since the gasoline storage and handling equipment at the plant belonged to Standard Oil (IN) (and was not leased to the operator) it was a subtle reminder not to use company equipment for products not supplied by Standard.
