As a child, I was fascinated with the paraffin dispenser fixed on the counter. It was a large glass cylinder with a rod running through the middle, on which were a number of metal discs.
With hindsight I realise that it was a graduated cylinder (probably a gallon), with the discs marking the various fractions of a gallon); but to my child's eye it looked like some sort of ornamental fountain and what's more, it was a magic fountain!
The shopkeeper (Mr Charles or Mr Finch?) would make some magical passes behind the counter (I was too short to see that he was working a hand pump to pump paraffin from a drum), and the cylinder would fill with blue paraffin. Then he opened a tap and poured the paraffin into the can which my mother had brought.