"This engine works a pair of vertical wheels inside that casing between the two divisions of the boat; and these wheels, which are each some eight feet in diameter and cogged, wind in the chains at one end, paying them out at the other." "I see," said Bob; and the floating bridge having by this time reached its terminus at the Portsmouth side of the water, they all stepped ashore and made their way home, Mrs Strong declaring that she had had "enough of going about, for one day at least!" In spite of her exertions, however, she was none the worse for them after dinner; being able, indeed, to accompany the others down to the beach, Rover now forming one of the party, and magnanimously forgiving his young master for leaving him behind all day in the house while he went gallivanting about sight-seeing, albeit Dick's company and Sarah's kindness in the way of tit-bits somewhat made amends to the poor dog for the neglect of the truant Bob.
"By the way," said the Captain to the latter, on taking his leave in the evening after escorting them back to "the Moorings," "you mustn't forget the trial of the _Archimedes_ to-morrow, my boy.

Captain Sponson told me the other day at the Club that she'd go out of harbour at nine o'clock sharp in the morning!" "Oh, I'll remember," replied Bob.

"Where will she start from, Captain ?" "Why, from Coaling Point, at the further end of the Dockyard; so we'll have to be under weigh half-an-hour earlier," cried the old sailor from the doorstep.

"You had better call at my place, as it is on the way.
Mind you're not later than 8:30 sharp, or she'll be off without you!" "I'll be there in time, never fear," was Bob's response as the Captain bade him "Good-night!" and stumped off homeward.

"I'll be in time!" Poor Rover! He was doomed to another day of desertion; for, much to his surprise, his young master, instead of taking him down to the sea as usual in the morning, started off alone, and without his towels, too, which puzzled Rover more than anything else.
Dogs have their feelings, similarly to other people; and so, his brown eyes filled with tears as he watched Bob rushing out of the house, in a terrible hurry lest he might keep the Captain waiting, or even, indeed, be too late altogether--with never a word for him save a peremptory, "Lie down, Rover; I can't take you with me; lie down, sir!" It was really too bad of Bob! In consequence of this unhandsome treatment, it may be likewise added, Rover's tail, which he generally carried in a jaunty fashion, with the trifle of a twist to one side, as became a dog of his degree and one moving in the best canine society, now drooped down between his legs--of a verity it almost touched the ground! This made the deserted animal look such a picture of misery that, on Nell's drawing her aunt's attention to him, the good lady of the house not only spoke sympathising words unto him, to which the sad dog replied by ever so feeble a wag of his drooping tail; but Mrs Gilmour also, sanctioned, nay, even directed, his being entertained with a basin of hot bread-and-milk served up on the best dining-room carpet, an event unparalleled in the annals of "the Moorings!" Bob meanwhile, with never a thought of Rover, was proceeding across the Dockyard with the Captain, who hobbled painfully over the knobbly paving-stones with which that national institution is ornamented, anathematising at every step he took the rulers of the "Queen's Navee," who put him thus to unnecessary pain.
"I can't think how, in a Christian land, people's poor feet should be so mercilessly disregarded!" he exclaimed, on giving his favourite corn an extra pinch between two projecting boulders--"I'd like to make `my Lords' of the Admiralty do the goose-step regularly here for four hours a day; and then, perhaps, there'd be a chance of a poor creature being enabled to walk about the place in comfort!" Notwithstanding the instruments of torture in the shape of paving-stones of which the Captain complained, and justly, he and Bob just managed to reach the _Archimedes_ before she cast-off from the jetty alongside of which she had been coaling, the two only having time to jump on board as the gangway connecting her with the shore was withdrawn.