"Of course, though," he added, "this fly-wheel was only available in stationary engines for pumping and so on; but, when the principle of the eccentric was discovered later in the day, the previously uneducated young giant, `Steam,' was then broken to harness, so to speak, being thenceforth made serviceable for dragging railway- carriages on our iron roads, and propelling ships without the aid of sails, and against the wind even, if need be!" "But what is steam ?" was Bob's next query.

"That's what I want to know." This fairly bothered the Captain.
"Steam ?" he repeated, "steam, eh?
humph! steam is, well let me see, steam is--steam!" Bob exploded at this, his merriment being shared by Nellie and Mrs Gilmour, the latter not sorry for the old sailor's "putting his foot in it" by a very similar blunder to that for which he had laughed at her shortly before; while, as for Dick, the struggles he made to hide the broad grin which would show on his face were quite comical and even painful to witness.
The Captain pretended to get into a great rage; although his twinkling eyes and suppressed chuckle testified that it was only pretence all the time, though his passion was well simulated.
"I don't see anything to laugh at, you young rascal," he said to Bob.
"I'm sure I've given you quite as good a definition as you would find in any of those `catechisms of common things'-- catechisms of conundrums, I call them--which boys and girls are made to learn by rote, like parrots, without really acquiring any sensible knowledge of the subjects they are supposed to teach! I might tell you, as these works do, that `steam was an elastic fluid generated by water when in a boiling state'; but, would you be any the wiser for that piece of information, eh ?" "No, Captain," answered Bob, still giggling, "I don't understand." "Or, I might tell you `steam: is only a synonym for heat, the cause of all motion'-- do you understand that ?" Bob still shook his head, trying vainly to keep from laughing.
"Of course not," cried the Captain triumphantly, "nor would I, either, unless I knew something more about it; and to tell you that would take me all the day nearly." "Oh spare us," said Mrs Gilmour plaintively.

"Pray spare us that!" "I will, ma'am," he replied.

"I assure you I wasn't going to do it.
Some time or other, though, this young shaver shall come along with me when one of the new ships goes out from the dockyard for her steam trials; and then, perhaps, he will be able to have everything explained to him properly, without boring you or bothering me." "How jolly!" ejaculated Bob.

"I should like that." "You mustn't count your chickens before they're hatched," growled the other, turning round on him abruptly; "and, if ever I catch you sniggering again when I'm talking I'll--I'll--" What the Captain's terrible threat was must ever remain a mystery; for, just at that moment, Nell, who had been looking over the side of the steamer, watching the creamy foam churned-up by her paddles and rolling with heavy undulations into the long white wake astern marking her progress through the water, suddenly uttered an exclamation.
"Look, look, aunt Polly!" she cried excitedly.