Hello! My father handed me this and asked if I could look it up (he's 84). He's good at finding random things either in the barn or cellar (or side of the road) and asking me to look up. I haven't been able to find this one though. The dial itself appears to maybe used to count either, at least we're guessing, how much was taken out or added to whatever it was attached to. With think it may have been something from my grandfather's oil truck (drove one in the 1930's and 40's) but my father doesn't remember where this initially came from since he had it hanging in the house for awhile. I've already contacted the Smithsonian archives to see what they could find in there but none of the catalogs they have showed this. Any help is appreciated (and my dad thanks you!)

Pictures:
https://1drv.ms/u/s!AgqnPtbJLGu3plf03uD0J-geWS4z
https://1drv.ms/u/s!AgqnPtbJLGu3pljKuYK052WFZzl2
https://1drv.ms/u/s!AgqnPtbJLGu3pkYkAwar8NbpJrWo

That is a gallon counter from an old bulk tanker truck. Moore & Kling was a pump company in Boston, MA. They manufactured gas pumps in the 1930s.

Yep, Eric's right. Those were found on old bulk tanker trucks and that's how the delivery person would keep track of the gallons dispensed. Not much value to it in the collector marker, but still a neat piece; particularly if it has some family connection.

Thank you both. That's what we were figuring but we were never quite sure. The bottom picture is my grandfather in his oil truck, would it be possible to be from that or is it definitely from a gasoline truck?

Nice pic of your grandfather and his truck ! Priceless

The panel just above the rear wheel is lettered: "RANGE OIL"
Range oil is "a high-boiling petroleum distillate for burning in the wick of an oil-burning kitchen range. The least volatile portion of the kerosine fraction"