From the context, it's clear that Catherine's candle is OUT.
"...she hastily snuffed it. Alas! It was snuffed and extinguished in one. A lamp could not have expired with more awful effect."
It says SHE snuffed it, and yet, TO HER SURPRISE, it was extinguished! Do not SNUFF and EXTINGUISH mean the same thing?
What am I missing here?