Nautical Economy. 95 



of strength, appear to present some comparative idea of the 

 accumulation of its strength ; but it is in the construction 

 of the egg, in which the wisdom of the Divine Author is 

 exhibited, that we must probably look for the nearest re- 

 semblance to it. The decks of a ship contribute above 

 water, in the straight part of the planking, to maintain the 

 form, but its sole security under the water depends on that 

 peculiar species of support mentioned above. 



It is proper to advert to one circumstance, hitherto not 

 noticed, in the discussion of this important subject, and 

 which appears to destroy the whole chain of reasoning ad- 

 duced for showing the strength of the diagonal system : — 

 we allude to the shrinking of the principal riders, against 

 which the secondary or truss timbers abut. This neces- 

 sarily leaves a vacancy at the extremities of the trusses, so 

 that they are totally ineffectual for their designed purposes, 

 till plates of iron, or other hard substances, are forced into 

 these interstices — a very common, we are told, and inconve- 

 nient practice. Abutments in ship-building are a very bad 

 species of support, as they receive the shocks to which a 

 ship is liable too suddenly ; but the diagonal system ap- 

 pears to be destitute even of the abutment, by the shrinking 

 of the principals. 



Whether the expense of constructing the navy on this 

 new system is greater or less than on that of the old, we 

 are unable to determine. — We are glad to see a mixture of 

 the diagonal riders and the ceiling now adopted in fri- 

 gates, instead of all wooden riders. 



As a convincing proof of the excellency of the diagonal 

 mode of placing part of the timbers of a ship, it has been 

 adduced that the French have again adopted it for trial, in 

 a few instances ; but here it must be remarked, that with 

 them time has not elapsed for the demonstration of its 

 value ; nor have wars, and other circumstances, occurred, to 

 decide the question. Our English merchant ship-builders, in 

 several cases of its adoption, have proved its inefficiency : 

 the steam-vessels, now built with it, sag, or drop down in 

 the middle, from six to twelve inches ; and we fear, on a full 

 view of the subject, its boasted advantages to our navy, 

 must fall to the ground. 



A more complete examination of the cross-carpentry of 

 Sir Robert Seppings, than the sketches hitherto before the 

 nation, is much required ; and as it involves the construction 

 of an immense navy, which costs twenty millions sterling to 

 replace, we hope it will soon appear. 



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