The Spouting Canal of the Sperm Whale

The spouting canal of the sperm whale is intended, as it is, for the conveyance of air. This curious canal is very much like a gas pipe laid down in a city on one side of a street. It cannot be proved that this is for the purpose of discharging water through the sphiricle. But how can you certainly tell whether any water falls from it? Can you not tell water from air? I have ever found your plain things the naughtiest of all.