of' Steam-power in Navigation. 239 



their place ; the more wood there is in the frame, the more it sufTer^ from 

 being thus water-logged, and the more the vessel sinks below its original 

 draught line, — the larger she is, the more she will labour in consequence, 

 and the more she will rack and strain her principal timbers; and If of a con- 

 struction to require caulking (that is to say, if carvel built), every time that 

 operation is renewed,— and it must be very frequently, — the wider will her 

 seams become, and the more she will depend for her safety on a little pitch 

 and oakum, on which, at the same time, the fire and motion will immediately 

 again act. I am assured that the present average duration of steam-boats is 

 only twelve years ; and there is little doubt that much of this rapid consump- 

 tion is owing^ to the undue weight of wood employed in them. And, if the 

 material could be changed altogether, and iron substituted (of which there 

 are, perhaps, some hopes •), the improvement would be very great- But, at 

 all events, smaller boats, clincher.built, would be some gain. And, if they 

 were fitted, moreover, with a light inside lining, a few inches from the side, 

 which would thus inclose a body of air to a certain extent stagnant, this 

 would operate as a palliative, as containing a non-conductor. And boats of 

 the construction here proposed would be particularly suited to receive this, 

 from their great breadth, and flat regular form. 



9. Steam-boats would thus also be a greatly more convertible property than 

 n(%, when, if they fail in paying on the particular service for which they are 

 built, they become a dead stock, too long, or too weak, too large, or too 

 small, or drawing too much water, for any other purpose at the moment in 

 the market, and thus incapable of being disposed of without a great sacrifice. 

 As thus proposed to be constructed they would all be strong, partly from the 

 peculiar arrangement of the materials which is favourable to strength, partly 

 merely because they would be shorter, great length in all vessels, but espe- 

 cially in steam-boats, occasioning weakness. They would likewise all draw 

 little water, nearly alike, and all be fitted, according to the measure of their 

 disposable power, for every possible service. And they would thus maintain 

 their value, like other vessels, in the market. 



And, lastly, when steam-boats shall be thus more cheaply built and main- 

 tained (an«l in this last particular also, I am persuaded that immense improve- 

 ment may be made, both as regards the production and application of the 

 steam |), — ^when they shall be more certainly saleable than now, — when they 



* Iron-vessels, besides being more durable for a particular service lik.> Uiat of steam, are cbeapcr 

 and more buoyant ; and the difflculty is not how to make them strong enough to go to Ma, but 

 how to protect them against the action of the salt water. The hopes now entertained are of ob- 

 taining a resin, yielding a simple, not a compound vamlsh, of auffldent body not to beaflbctfld by 

 any heat proceeding from the fire, at the same time so clastic as that it shall not crack with the 

 motion of the vessel, and impenetrable by water. 



t In districts where fuel is scarce and dear, a saving is made by mixing up clay and other ingre- 

 dients with the coals uoed ; and it has been said that some experiroenu of this kind. lately nude hi 

 London, in steun-furaacM, have been very nieecMAil. Certain fonnt tt boOen lately paloitad. 

 promise also a large economy in the quantity of fuel used. Improved peddles will probably do 

 something : systematic abatement of speed, in all easee which wiU not admit of a liberal eapence, 

 more; and much would be abo gained by a greet range of power, both up and down, eo that ai es- 

 pence is incurred in unfavourable draunatanoce, a ootieqMBdlng «vfa(g nay be Bade iihen they ve 

 favourable. (And it is in this last point of view that two enginea to be uaed almaMy or Uvethar, 

 as required, a number of small boUen instead of two fanrgef and high preKure steem worked oxpOK 

 sively, appear to me so peculiarly eligible in navigatioii, in which the resistance to be overcome nMai 



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