The steam engine familiarly explained and illustrated; with an historical sketch of its invention and progressive improvement; its applications to navigation and railways; with plain maxims for railway speculators. By the Rev. Dionysius Lardner ... With additions and notes by James Renwick ...

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CHAPTER XII.
STEAM NAVIGATION.
1'ropaismi by Paddle Wheels.-Manner of driving them.-Marine Engine. —
Its Form and Arrangement.-Proportion of its Cylinder.-Injury to-Boilers
by Deposites and Incrustation.-Not effectually removed by blowing out.Mr..Samuel Hall's Condenser.-Its Advantages.-Originally suggested by
Watt.-Hall's Steam Saver. —Howard's Vapour Engine.-Morgan's Paddle
Wheels.-Limits of steam Navigation.-Proportion of Tonnage to Power.Average Speed.-Consumption of Fuel. —Iron Steamers.-American Steam
Raft.-Steam Navigation to India.-By Egypt and the Red Sea to Bombay.
-By same Route to Calcutta.-By Syria and the Euphrates to Bombay.Steam Communication with the United States from the west Coast of Ireland
to St. John's, Halifax, and New York.
(114.) AMIVoNG the various ways in which the steam
engine has ministered to the social progress of our race, none
is more important and interesting than the aid it has afforded
to navigation. Before it lent its giant powers to that art,
locomotion over the waters of the deep was attended with a
degree of danger and uncertainty, which seemed so necessary
and so inevitable, that, as a common proverb, it became the
type and representative of every thing else which was
precarious and perilous. The application, however, of steam
to navigation has rescued the mariner from much of the
perils of the wTinds and waves; and even in its actual state,
apart from the improvements which it is still likely to
receive, it has rendered all voyages of moderate length as
safe and as regular as journeys over land. WVe are even
now upon the brink of such improvements as will probably
so extend the powers of the steam engine as to render it
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