Steam Navigation, Its Rise and Progress, with Authentic Tables of the Extent of the Steam Marine of All Parts of the Globe, Contrasted with the Steam Power of the British Empire

have thus only to offer my desire to do justice to a talented individual, whose neglect was in proportion to his merit, and a collection of facts, that may not be useless for reference, for this badlyarranged and immature production; the first effort of a writer without experience in the graces of composition, unpremeditated, and wholly unexpected. Much will appear repetition; but allowance will be made for the circumstance that I have taken up the subject only as opportunity allowed me, and never continued it three hours together. Neither must it be forgotten, the difference between stating a fact and establishing one; a sentence may serve for the first, a volume sometimes is required for the other, if the writer seeks (what, to avoid the cacoëthes scribendi replies, every writer ought to seek, or else not attempt at all,) to set a disputed question at rest for ever. Had I paid as much attention to the arrangement and composition as I have done to accuracy in the data and Tables, I should ask no indulgence. Obliged to notice the Steam Engine, in tracing its application to Navigation, I took the opportunity of treating its history in a manner entirely new, especially in distinguishing more prominently, at pages 75 and 76, what has always been the criterion of its excellence-the method of condensation. I sought also to give to this wonderful machine those attractions for the general reader which I had not seen elsewhere, embracing, at the same time, all the information necessary for this class of readers, but not that knowledge, which none but the engineer requires. Doubtless, without drawings, it may be difficult to convey a clear impression of the different improvements on the Steam Engine; but, believing that what is seen distinctly can be described accurately, I have depended upon this simple resource, and familiar words, to convey the meaning. I would observe that I have little confidence in

APOLOGETICAL PREFACE.

awarding, at page 70, the merit of the first Steam Engine erected in England, to the Marquess of Worcester. My authority for this novel statement will be found at page 325 of the Travels of Cosmo the Third, in Great Britain, in the reign of Charles the Second, in 1669, not 1653, as stated. Though I have been puzzled what other machine to understand by it, the description is not sufficiently clear to my mind, to leave no doubt of its being the steam engine. The paddle-wheel here described may be considered an improvement upon the common wheel for Sea Navigation, yet I certainly give the preference, for such purpose, to Smith's Screw Propeller, which, since these pages were struck off, has attracted considerable attention as applied to the "Archimedes." It is needless to dwell upon superiority so evident, as the certainty of an easy moving power being, under all circumstances, immersed to its proper depth, over the variable dip of paddle-wheels, one of which is frequently immersed up to the axle, whilst the other is revolving in the air. The propeller, besides, possesses many collateral advantages superior to any paddle-wheels, and will no doubt completely supersede them. Whether it possesses equal power in smooth water is questionable, but at sea any loss is more than supplied. Altogether it is a very great improvement in Steam Navigation.

The horizontal Windmill, here noticed, is better calculated than any other yet invented, to set at rest the long disputed question in mechanical science, whether any horizontal Windmill can have more power than the vertical mill?

Hitherto the experiments cannot

be considered conclusive, on account of the great friction of the feathering motion of horizontal mills; but in the one now noticed this is reduced to the smallest possible amount, to far less, indeed, than in the best vertical mill, and being quite a new motion so applied in mechanics, it becomes an interesting problem to determine,

Mr. Symington's inventions being recorded in these pages, it may be proper to observe that he is not responsible for any errors, as I was not able to avail myself of any suggestions in the MS. or the proofs. Errors, though I believe not errors of principles, may therefore be discovered, but the discriminative reader will not consider them sufficient to entitle what is sound in itself to no confidence. have said thus much, aware that when we have been accustomed to let great names think for us, unless the authority of a great name meet us in the title-page, we are frequently but too little inclined to consider worthy of dependence the work of an unknown writer. We do not trouble ourselves to invalidate by argument what he writes, but adopt the much shorter course of destroying its value by prejudice. Much of what is here written may be found opposed to the opinions, the prejudices, and interests of others. Do I then expect too much in requesting that it may not be merely asked who writes it, as if that alone were sufficient to carry refutation or conviction of a novel assertion, but that the substance may be proved erroneous, if it be so? When we seek principles for the foundation, and apply common sense for the scaffolding, we may hope to attain, by just degrees, to the eminence of truth; and, as I hope always to remain open to conviction, I shall thankfully receive whatever may convince me of error.

It is difficult in a first attempt to acquire that rigorous self-control to prevent straying from the text. I have thus exposed myself to the "swashing blow" of the ingenious critic, who will find in this, as probably in most early works, "ample room and verge enough" for the exercise of much pleasant banter.

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