12G Report of the Hause of Commons on Sicam-Boats. 



tioiis made by deposited salts in the boilers, through neglect 

 to change the water and clean the boilers ; and Mr. Donkin 

 savs he has known great inconvenience from the same cause. 

 In one instance, going to Margate, one out of three boilers in 

 the vessel produced very little steam, in consequence of the 

 incrustations on the bottom, a circumstance that was disco- 

 vered by its requiring very little water to be introduced into it. 

 Mr. Dnnkin further says, that he knows only of two methods 

 by which the deposition of salt can be prevented. " In the 

 Regent steam-boat, they employed a method very successfully, 

 that of pumping hot water through the boiler, and allowing a 

 certain quantity constantly to be discharged from it into the 

 sea ; by these means the water was always kept in a sufficiently 

 diluted state, so as to prevent its becoming saturated with salt, 

 and conseciueutly none could be deposited. No other incon- 

 venient effect was produced than a greater consumption of 

 fuel. The other mode is the ccmmon and ordinary one of 

 taking out the whole of the water when the vessel arrives at 

 the place of destination, and if there is any deposit of salt, 

 taking that out also." 



In consequence of the injury which sea-water does to iron, 

 Mr. Cooke recommends that the air-pump, buckets, rods and 

 valves, should be made of copper or brass. 



It is necessary that great care should be taken in selecting 

 coals to be used in steam-boats ; they ought to burn free and 

 become complete white ashes, without cakh)g on the fire bars. 

 Mr. Brown says, " that in the first )jassage he went in the 

 City of Edinburgh to Leith, they were obliged to clear the 

 lire every four hours ; but having gut a better description of 

 coals at Leith, called Halbeath Main, they went, in coming 

 back, sixteen hours Avithout clearing the grates." — Mr. Donkin 

 says, " I think the coals ought to be particularly attended to; 

 first, the kind of coals, and secondly, to avoid taking small 

 coals, so long as the common fire-places are used ; small coals 

 occasion great waste ; and all coals employed for steam-boats 

 ought to be scree led*." There is another reason why atten- 

 tion should be paid to the selecting and managing of the coals, 

 arising from their tendency to fire spontaneously, if put to- 

 gether in large quantities in a damp state, and then exposed 

 to the heat of a steam-boat. 



It w411 be seen by the evidence, that the consumption of fuel 

 differs very much, according to the various plans on which the 

 engines are constructed, even where the steamhig power is the 

 same. 



• See Evidence of Mr. Donkin, p. 172, and of Mr. Faraday, p. 190. 



In 



