Moby Dick by Herman Melville Chapter 85 Page 9

whether the spout of the Sperm Whale is the mere vapor of the exhaled breath, or whether that exhaled breath is mixed with water taken in at the mouth, and discharged through the spiracle. It is certain that the mouth indirectly communicates with the spouting canal; but it cannot be proved that this is for the purpose of discharging water through the spiracle. Because the greatest necessity for so doing would seem to be, when in feeding he accidentally takes in water. But the Sperm Whale’s food is far beneath the surface, and there he cannot spout even if he would.

Besides, if you regard him very closely, and time him with your watch, you will find that when unmolested, there is an undeviating rhyme between the periods of his jets and the ordinary periods of respiration.