HISTORY OF MARINE ARCHITECTURE.

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remembered, become almost useless, unless they are impelled with quickness andspirit, as well as brought back to their original station, for a renewal of thestroke, with equal celerity. The mechanical powers are of no use in thisinstance, as the law remains fixed and immutable, that if any operation, which,in the ordinary course of things, requires ten men to perform it, and one only isemployed about it-, it may indeed be executed by that one, but will require aperiod ten times as long to perform it in ; for nature will not suffer herself tobe deceived, or her laws perverted, by any such vainly hoped for advantage.”

That the various inconveniences and obstacles, which attend the system ofallotting one man only to work the higher tiers, may be clearly understood,and further, that we may fully satisfy ourselves what can and what cannot bedone, let us enquire into the size and weight which it is necessary the oars in theupper tiers should, and indeed must have been. Those who wish to allow aslittle distance as possible between them, have never ventured to assign less thaneighteen inches : it follows, therefore, that the uppermost tier would be no lessthan sixty feet from the surface of the water ; in which case, it is very evident,as has been already' observed, that an oar, being in length only fifty-seven feet,could not even touch it. To pursue the subject as closely as it ought to be,and state precisely the necessary length of an oar, whose fulcrum, or row-lockport, is raised sixty feet above the surface of the water ; it is very evident, thatthe length of an oar should be three times that of its perpendicular height, fromthe water itself: this will give no less than one hundred and eighty feet, exclusiveof the handle, and such part as reaches within board.

The position and arrangement of the rowers is next to be considered, the inter-spaces that were left, as well between them as the row-lock ports, togetherwith the disposition of the seats on which they sat. The coins of the ancients,on which the representations of the Trireme, and that class of gallies, calledLiburnae, are very frequent, afford but little assistance, because (it is said onaccount of the smallness of the scale) it is not possible ever to express on themmore than one tier of oars. On the coin, however, of the emperor Gordian,two are very conspicuous ; on the Trajan column, as well as other remnantsof ancient sculpture, positive proofs occur of three tiers of oars, placed obliquelyabove each other. From this vague and very inconclusive evidence, manyvery learned men have been induced to believe and assert, that those vessels whichare represented in ancient history as of superior rate to Triremes, rose in regularprogression with regard to their number of tiers, up to that (the existence and

form