"You don't happen to mean that the Flying Dutchman has appeared on the Scotch coast, do you, Willis?"
"Not a bit of it, I mean just exactly what I say. It is a real ship, with a real stern and a real figure-head, but manned by blacksmiths instead of mariners."
"Well, but how does it move? Does somebody go behind and push it, or is it dragged in front by sea-horses and water-kelpies?"
"No, it moves by steam."
"But how?"
"Aye, there lies the mystery. The affair has often been discussed by us sailors on board ship; some have suggested one way and some another."
"Neither of which throws much light on the subject," observed Jack; "at least, in so far as we are concerned."
"All I can tell you," said Willis, "is, that the steam is obtained by boiling water in a large cauldron, and that the power so obtained is very powerful."
"That it certainly is, if it could be controlled, for steam occupies seventeen or eighteen hundred times the space of the water in its liquid state; but then, if the vessel that contains the boiling water has no outlet, the steam will burst it."
"It appears that it can be prevented doing that, though," replied Willis, "even though additional heat be applied to the vapor itself."