A device that made carbonated water for alcoholic drinks. A chemical reaction in the upper chamber forced carbon dioxide in the lower chamber, mixed with water and was delivered through the spout. They sometimes exploded (notice the mesh covering the glass).
Another liquor related object is the tantalus, which is a contraption that can lock liquor decanters (bottles). Unfortunately, Sherlockians are divided whether the tantalus is Canon.
Gasogene is also a term used to refer to the leader and organizer of a scion society.