I believe it held kerosene.
It's a kerosene reservoir for a kerosene kitchen range. The clue is the valve stem sticking out the top of the lid. This jug sat at on the end of the range and fed kerosene into a small pipe. The pipe ran the length of the stove. Each burner was plumbed with short pieces of tubing to the supply pipe.
After filling the jug, it was quickly up ended over its receptacle and sat down. The valve in the lid was depresed opening the cap to feed the fuel. The fuel would bubble out until the fuel level covered the opening in the lid. At this point, air is shut off from getting into the jug and atmospheric pressure holds the fuel in the jug. Works just like a jug of bottled water on a water dispenser.
It s critical that the stove be leveled. If the far end of the stove is too low, the fuel will spill out the last burner and dump the contents of the reservior. If the jug end of the stove is too low, the burners at the far end will starve for fuel. Usually, the oven was at the far end. A typical range had 4 burners and an oven.
The burners had circular wicks that sat in a pool of kerosene. The wick was raised for lighting and burning. The height of the flame was regulated by the height of the wick. To put out a flame, the wick was lowered into its shield. This cooled the fuel at the top edge of the wick to below ignition temperature and the flame would go out - hopefully.
When turning the jug over to place it on the stove, it often dribbled a little fuel because that valve in the lid did not make a perfect seal. That'a why one did not invert the jug until it was directly over its receiver.
As you may well guess by now, those old kerosene ranges were big fire hazards.
The kitchen floors in old farm houses were often not level. It was not unheard of to see some wood blocks under a couple of legs to aid leveling. I've seen floors that were so uneven they was beyond the range of the levelers built into the legs of the stove. This was s disaster waiting to happen. Picture the house wife canning jams and jellies and the burners are going full blast when a child walks by and stubs a toe on one of those blocks kicking it away. The stove drops at the corner, the pots nearly spill, and recall what the kerosene does when the stove is grossly unleveled. It is really a scramble if its the far end of the stove that is dropped.
How do I know? We had one in our house during the early 1940s when I was a child. Although it was convenient, we got rid of it and did all the cooking on a wood fired range.