A candle would get blown out is waved about or in draughts and the bottle doesn't look like a candle would burn inside. Surely it'd need to be some sort of lamp and stick to test for CO2 rather than bottle? (or a stick with a lump on the end for carrying a lamp, like a deputy stick)
Stating the obvious, it looks like a small bottle on a stick (assuming the bottle is supposed to live there).
Why would someone want that?
Collecting a liquid sample from a hard to reach location, maybe collecting seepage from somewhere?
Pouring a small quantity of liquid on a hard to reach location
Pouring a small quantity of powder on a hard to reach location
If it's a prospect, it has to be something to do with sampling?