xcviii ADVERTISEMENT.

often branched out into a variety of sections and divisions, in which the greater partof their readers feel themselves very little interested. An History of Marine Archi-tecture is peculiarly subject to this species of objection. The mere theorist maycovet to learn only what has been done in remote times, that he may furnish him-self with a general and comprehensive view of the subject, from whence, in the hopeof suggesting improvement, his own future studies may be directed towards any pointwhich he finds most suited to his inclination. On the other hand, the practical artist,totally disregarding obsolete fashions and customs, which he considers as in no degreeinteresting to him, wishes for nothing more than the possession of such designs as themost recent experience has established the propriety of. The reason of this differenttendency of the human mind, is obvious in both instances. The former character hassufficient leisure to bend his views to scientific improvement, while the latter is pre-vented, by the natural duties of his occupation, from paying the same portion ofattention to it: he consequently resorts to his fellow labourer for assistance, orreadily embraces and pursues such as suit his purpose, from among the experimentsthat have been made by other artists, to whom, in his turn, he himself affords thesame kind of aid.

What is now offered, therefore, to the public, is an historical account, and anhumble attempt, towards the investigation of the theory of the science. The characterof the generality of those readers, to whom the consideration of such branches maybe most agreeable, has been already hinted; and though, it is hoped, it may not betoo arrogant to expect, that many, even practical men, may possess sufficient curiosityand leisure to honour the following sheets with a serious and attentive perusal, yetit certainly might be considered, by others, an extravagant tax upon them, to compelthe purchase of what they might esteem least consequential, as the sole means of pos-sessing that which they might deem infinitely more valuable. In respect to the meritsof the present Publication, the Author, as he has just now hinted, is naturally doubtful.It is a work of labour, and of inquiry ; and of the extent of his own faculties in thosepursuits, no man is a competent judge. As to the proposed Supplement, which hasnothing but truth, and usefulness to recommend it, he entertains no fears for its recep-tion. It will contain merely a detail of facts, collected from the dry experience ofpractical men ; and if he reports them with fidelity and accuracy, he will have done

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