CHAPTER TEN.
AFLOAT--AND ASHORE.
"Sure, I'm almost dead entirely, with all that hurrying and scurrying!" exclaimed Mrs Gilmour, when she was at length got safely on board the little steamer and comfortably placed on a cosy seat aft, near the wheel, to which Captain Dresser had gallantly escorted her.

"Really, now, I couldn't have run another yard, if it had been to save me life!" She panted out the words with such a racy admixture of her Irish "brogue," which always became more "pronounced" with her when she was at all excited in any way, that the Captain, even while showing every sympathy for her distressed condition, could not help chuckling as he imitated her tone of voice and accent--much to the amusement of Master Bob and Miss Nellie, you may be sure! "Sure, an' there's no knowin' what ye can do, now, till ye thry, ma'am!" said he.

"Is there, me darlint ?" "None of your nonsense," she replied laughing; "I won't have you making fun of my country like that.

I'm sure you're just as much an Irishman as I am!" This slip delighted the Captain.
"There, ma'am," he exclaimed exultingly, "you've been and gone and put your foot in it now in all conscience." "Oh, auntie!" cried Nellie, "an _Irishman_!" This made Mrs Gilmour see her blunder, and she cheerfully joined in the laugh against herself.
Bob, meanwhile, had stationed himself by the engine-room hatchway, and was contemplating with rapt attention the almost human-like movements of the machinery below.
How wonderful it all was, he thought--the up and down stroke of the piston in and out of the cylinder, which oscillated from side to side guided by the eccentric; with the steady systematic revolution of the shaft, borne round by the crank attached to the piston-head, all working so smoothly, and yet with such resistless force! The whole was a marvel to him, as indeed it is to many of us to whom a marine engine is no novelty.
"Well, my young philosopher," said the Captain, tapping him on the shoulder and making him take off his gaze for a moment from the sight, "do you think you understand the engines by this time, eh ?" Bob only needed the hint to speak; and out he came with a whole volley of questions.
"What is that thing there ?" he asked, "the thing that goes round, I mean." "The paddle-shaft," replied the Captain; "it turns the wheels." "And that other thing that goes up and down ?" "The piston-rod," said the old sailor.

"It is this which turns the shaft." "Then, I want to know how the piston makes the shaft turn round, when it only goes up and down itself ?" "The `eccentric' manages to do that, although it was a puzzle for a long time to engineers to solve the problem--not until, I believe, Fulton thought of this plan," said the Captain; and, he then went on to explain how, in the old beam-engine of Watt, as well as in the earlier contrivances for utilising steam-power, a fly-wheel was the means adopted for changing the perpendicular action of the piston into a circular motion.