faults of the work upon its head, and I have been too much engaged in the
practical construction of steam ships and steam engines to find time for
the thorough revision which I knew the work required. At length, however, I
have sufficiently disengaged myself from these onerous pursuits to
accomplish this necessary revision; and I now offer the work to the public,
with the confidence that it will be found better deserving of the favorable
acceptation and high praise it has already received. There are very few
errors, either of fact or of inference, in the early editions, which I have
had to correct; but there are many omissions which I have had to supply,
and faults of arrangement and classification which I have had to rectify. I
have also had to bring the information, which the work professes to afford,
up to the present time, so as to comprehend the latest improvements.

For the sake of greater distinctness the work is now divided into chapters.
Some of these chapters are altogether new, and the rest have received such
extensive additions and improvements as to make the book almost a new one.
One purpose of my emendations has been to render my remarks intelligible to
a tyro, as well as instructive to an advanced student. With this view, I
have devoted the first chapter to a popular description of the Steam
Engine--which all may understand who can understand anything--and in the
subsequent gradations of progress I have been careful to set no object
before the reader for the first time, of which the nature and functions are
not simultaneously explained. The design I have proposed to myself, in the
composition of this work, is to take a young lad who knows nothing of steam
engines, and to lead him by easy advances up to the highest point of
information I have myself attained; and it has been a pleasing duty to me
to smooth for others the path which I myself found so rugged, and to
impart, for the general good of mankind, the secrets which others have
guarded with so much jealousy. I believe I am the first author who has
communicated that practical information respecting the steam engine, which