on the respective subjects of starting and stopping. This, in itself, is evidence of almost human strength of character. In all experience it has been found that large bodies move slowly-an ancient adage, beautifully illustrated in the case of the Clara Clarita. (G.)

"It was D- -n who selected the boiler and adapted the machinery of that thing of beauty,' at a cost, to the gifted Jerome, of over Twenty-One Thousand Dollars. And she sailed precisely one mile and a quarter in two hours and a half, being ultimately thwarted by a stubborn and unaccommodating tide, at Corlear's Hook. Equally valid is the venerable adage as applied to all Dn engines, with their inevitable cut-off. They start slowly; they run with dignity; they stop with due deliberation. In watching this one, I am often reminded of an old gentleman, whose girls I used to flirt with, when I was a boy. A solid old gentleman he was-with the gout, and a purple nose, and staunch conservative views; and he sat by night in his drawing-room, in a marvellous arm-chair, his noble form arrayed in indescribable com

plications of raiment. 'Good evening, sir,' I used to say to him, on entering the room: 'it's a very cold evening.' And then I turned my attention to the girls. But the old gentleman's brain was an active one; and, after precisely fifteen minutes of preparation, his voice, emerging from many bandages, would be heard to answer, 'Yes, you're rightthe evening is very cold.' There was a solidity about that old gentleman, very impressive to me in those days; and there is a similar and equally impressive solidity about this D-n engine. If it has a fault; that fault consists in its insufficient illustration of its erudite author's idea upon the subject of bricks. With that idea he electrified a Washington Jury, in the Mattingly Case, and that idea once fully realized. in practice, would electrify the entire mechanical world. Imagine a platform supporting a ton of bricks (H), placed upon the end of a oneinch piston! Transport that image to yonder engine-room, and mark the consequence.

'How reason reels!

O what a miracle to man is man,' especially when he happens to be such a man as D

-n.

Here conticuere omnes, and the black bottle was circulated. But my eloquent friend, absorbed in the grand theme, soon continued his eulogium.

"The genius of D- -n has been otherwise made manifest in four enormous rock-shafts, garnished with numerous parabolic cams, and designed for working the steam-exhaust and cut-off valves. It appears, too, in the valves themselves, upon which all manner of intricate instruments have been ingeniously brought to bear, in order to prevent any abrupt and decisive action that should by chance resemble that of vulgar machinery. I think it was the sublime purpose of D―n, in reference to this engine, that it should display 'neither variableness nor the shadow of turning.' His liberal ingenuity has combined the heavy metals as never heavy metals were combined before. Not only has he contrived a dash-pot, to prevent the slamming of the cut-off valve; but he has devised a lip to cushion on the steam as it is jammed against the valve-seat. I dwell upon these details with a fascinated interest. This valve is plug-shaped. On its outside rim is a ring of metal laid upon the seat, and designed to give lead to this plug-arrangement, by expanding or contracting its circle. You can have no conception of the felicity with which it works, unless you have both seen and heard it. The principle is that of the organ-pedal, while the music-but what words can do justice to the incessant click, click-up, sh, clickety-click, click-up, so clear, so distinctly intoned, so soothing to the nervous system! What says the poet Milton?

"I think not.

Can any mortal mixture of earth's sound,

Breathe such divine, enchanting ravishment!'

"You will marvel, perhaps, that such surpassing excellence of mechanism is not more widely appreciated in this scientific generation. I must remind you of Galileo

who was incarcerated for his
intelligence; and of the Scottish
inventor of umbrellas, who was
pelted in the streets for bearing
up one of his own anti-pluvial
protectors. It was not easy for
even the mighty Dn to
persuade Uncle Samuel to buy
the whistle. The very machin-
and modest un-
itself-coy
der the eye of distrustful obser-

ery

www

Cut off Valve.

vation-declined at first to operate. I recall the trial day of the Pensa

cola. The great engineer himself was on board, to superintend the engine. All was excitement. Promptly, at the word of command, the

dash-pot phalanx seized their implements, and rushed into action. Gallant charge! I beheld it from my station at the valves, and thought that I had never seen a more extraordinary proceeding towards an engine. We made, I think, some ninety odd trials before the link would

rise, and the desired, and I may say, indispensable vacuum, consent to form. Coyness, as I have said, is the vice of this wonderful engine;

Working Water-valves-A recreation in hot weather.

but, to cull once more from those sweet pastures of song in which its inventor loves to ramble,

I have since noticed other manifestations of that coyness. For example, this ship has excellent lines for sailing. With a ten-knot breeze, she can out-sail her modest engines entirely. They are sensitive and sluggish under ordinary treatment. We have sometimes made nine knots an hour, with the vessel under sail, and the engines doing their utmost. That was brilliant! But coyness would seem to settle upon those cogs, and paralyze those dash-pots; and then we have disconnected the propeller, and so made eleven-and-a-half or twelve knots under the same amount of sail. At such times, the engine may have attained from forty to forty-four revolutions, cutting off, as indicated by the cut-off dial, at three and one-tenth of the stroke. Steam, as you know, soon works off; but by using the best of coal, and keeping the firemen in a state of incessant and wholesome activity, we have managed to keep up fourteen pounds; which implies that, under certain circumstances, a great number of revolutions may be attained by dragging the propeller through the water as you bowl merrily along.

E