iv PREFACE.

benefit of such remarks as have been elicited by the writings of theirown countrymen.

The Sketch accordingly commences by detailing facts which de-monstrate that the use of the Paddle-Wheel as an instrument for pro-pelling boats or vessels is of great antiquity, preceding by ages thefirst suggestion of the application of steam as a motive power for thatpurpose.

This is succeeded by a recapitulation of the early projects for pro-pelling vessels by the aid:of the steam engine, and of the variousmodifications proposed or practically adopted at subsequent periods;thus placing before the reader the means of forming a just estimate ofthe pretensions of the several projectors to be ranked as fhe realauthors of the present System of Steam Navigation.

In conclusion, some of the instruments denominated Screw Pro-pellers are duly noticed, with authentic statements of the results ofvarious experiments in which they were applied, and remarks onthose generally in use in Europe and in the United States of Ame-rica.

It will be obvious that the facts thus detailed were widely scat-tered, and in some few instances difficult of access: they have con-sequently been collected and arranged from many sources, and thecompilation is now submitted as forming a book of reference whichmay be found not only useful, but interesting to those who seek forinformation as to the origin and progress of Steam Navigation.

B. WOODCROFT.

1, Furnival’s Inn, Holborn,November, 1848.