I'm sure you just had a hard time making out the actual lamp, as the home made candles compete with LED's more often than not!
That that looks like a carbide lamp. Calcium carbide (
calcium acetylide CaC2) mixed with water produces acetylene gas...it's what the miners used in their lamps way back in the day....or if you had a toy carbide cannon (typically sold on the last page of comic books...if you remember).
Imagine the issues those miners had when they broke into a vein of methane gas with that open flame.
I remember being able to buy calcium carbide from the local hardware store back in the mid 80s. It was fun filling up a ziploc bag with acetylene and setting it off with a fuse.
Kids today will never know the fun we had back then.
But on a side note, from Wikipedia, your sign vinyl is also dependent upon the stuff:
"In China, acetylene derived from calcium carbide remains a raw material for the
chemical industry, in particular for the production of
polyvinyl chloride".
Original source:
https://en.wikipedia.org/wiki/Calcium_carbide
JB