er to constantly in the course of his practice.
This work may be bound up with the "Catechism," if desired, to which it is
in fact a Key.

I shall thankfully receive from engineers, either abroad or at home,
accounts of any engines or other machinery, with which they may become
familiar in their several localities; and I shall be happy, in my turn, to
answer any inquiries on engineering subjects which fall within the compass
of my information. If young engineers meet with any difficulty in their
studies, I shall be happy to resolve it if I can; and they may communicate
with me upon any such point without hesitation, in whatever quarter of the
world they may happen to be.

JOHN BOURNE.
9 BILLITER STREET,
LONDON,

_March 1st, 1856_.

PREFACE

TO THE FIFTH EDITION.

The last edition of the present work, consisting of 3,500 copies, having
been all sold off in about ten months, I now issue another edition, the
demand for the work being still unabated. It affords, certainly, some
presumption that a work in some measure supplies an ascertained want, when,
though addressing only a limited circle--discoursing only of technical
questions, and without any accident to stimulate it into notoriety,--it
attains so large a circulation as the present work has reached. Besides
being reprinted in America, it has been translated into German, French,
Dutch, and I believe, into some other languages, so that there is, perhaps,
not too much vanity in the inference that it has been found serviceable to
those perusing it. I can with truth say, that the hope of rendering some
service to mankind, in my day and generation, has been my chief inducement
in writing it, and if this end is fulfilled, I have nothing further to
desire.

I regret that circumstances have prevented me from yet issuing the
"Hand-Book" which I have had for some time in preparation, and to which, in
my Preface of the last year, I referred. I hope to have sufficient leisure
shortly, to give that and some other of my literary designs the necessary
attention. Whatever may have been the other impediments to a more prolific
authorship, certainly one of them has not been the coldness of the
approbation with which my efforts have been received, since my past
performances seem to me to have met with an appreciation far exceeding
their deserts.

JOHN BOURNE.

_February 2d, 1857_.

PUBLISHERS' NOTICE.

In offering to the American public a reprint of a wor