"That name is given it because of the elevation of the upper surface of the head above the rather short beak and in front of the blow hole into a rounded abrupt prominence."
"Blow hole," repeated Ned, wonderingly; "what's that, papa?"
"The blow holes are their nostrils through which they blow out the water collected in them while they are down below the waves. They cannot breath under the water, but must come up frequently to take in a fresh supply of air. But first they must expel the air remaining in their lungs, before taking in a fresh supply. They send that air out with great force, so that it rises to a considerable height above the water, and as it is saturated with water-vapor at a high temperature, the contact with the cold outside air condenses the vapor which forms a column of steam or spray. Often, however, a whale begins to blow before its nostrils are quite above the surface, and then some sea-water is forced up with the column of air."
They were watching the whale while they talked; for it followed the yacht with seeming curiosity. At this moment it rolled over nearly on its side, then threw its ponderous tail high into the air, so that for an instant it was perpendicular to the water, then vanished from sight beneath the waves.
"Oh, dear," cried Ned, "he's gone! I wish he'd stayed longer."
"Perhaps he will come back and give us the pleasure of seeing him spout," said the Captain.
"Do you mean throw the water up out of its nostrils, papa?" asked Ned. "Oh, I'd like that!"
"Ah, there's the call to supper," said his father, as the summons came at that moment. "You wouldn't like to miss that?"
"No, sir," returned Ned, in a dubious tone. "But couldn't we let the supper wait till the whale comes up and gets done spouting?"
"Perhaps some of the older people may be too hungry to wait comfortably," returned his father; "and the supper might be spoiled by waiting. But cheer up, my son; the whale is not likely to come up to the surface again before we can finish our meal and come back to witness his performance."