A candlebomb is a small bubble of glass, filled with water. Placing this in the flame of a candle will cause the water inside to heat, turning it to steam and causing the glass shell to burst. The question is... why? What possible use could such a device be?
Well, not unlike the indoor fireworks which were popular during the eighties, the after dinner amusement device of choice in the eighteenth century was the candlebomb, whereby any number of guests could be held in fascinated thrall by the evanescent bang of an exploding glass sphere.
It's hard to understand why it didn't catch on... naked flames, hot water and splinters of glass on the table are so much more sophisticated than wafer thin mints.