ON

MODERN SYSTEMS OF FORTIFICATION,

INCLUDING THAT PROPOSED BY M. CARNOT,

AND A

COMPARISON OF THE POLYGONAL WITH THE BASTION SYSTEM;

TO WHICH ARE ADDED,

SOME REFLECTIONS ON INTRENCHED POSITIONS, AND A TRACT ON THE
NAVAL, LITTORAL, AND INTERNAL DEFENCE OF ENGLAND.

BY

GENERAL SIR HOWARD DOUGLAS, BART.,

G.C.B., G.C.M.G., D.C.L., F.R.S.,

AUTHOR OF A TREATISE ON NAVAL GUNNERY,' ETC.

With numerous Illustrations.

LONDON:

JOHN MURRAY, ALBEMARLE STREET.

1859.

The right of Translation is reserved.

LONDON: PRINTED BY W. CLOWES AND SONS, STAMFORD STREET,

PREFACE.

On the occasion of offering to the world a reprint of a work published more than forty years since, the author is desirous of explaining the reasons which have induced him to revert, at this distance of time, to a subject then justly thought to be of much importance; but which to many has appeared since to have lost its interest, and, for the object originally proposed in its publication, not to admit of being revised with any practical advantage.

One of the reasons, as the author hopes to show, is that the subject, far from having lost any of its interest, assumes now a degree of importance greater than ever. What was, nearly fifty years since, only a theory has now been reduced to practice: the principles of M. Carnot having been extensively adopted by Prussian and Austrian engineers, in re-modelling the fortresses of their countries, and in constructing new ones. The strength and security of these, are objects of the most vital importance to all those nations by whose exertions, in one common alliance, the great war arising out of the French Revolution, in 1793, was brought to a successful termination. Europe was delivered from a state of humiliating subjugation, and rendered capable of