TRANSACTIONS OF THK SKCTIONS. 131 



bushel of coal might be considered equivalent to eighty millions lifted 

 in a pumping engine. Taking the quantity of water lately found, chiefly 

 through the exertions of John Taylor, Esq., to have been evaporated per 

 bushel, it was shown that the cubic feet of steam which could be 

 formed by the consumption of the known quantity of coal per month, 

 would readily supply the quantity of steam required in the cylinder 

 per month, and be capable of producing at each stroke a mean pressure 

 in the cylinder equal to the sum of the work done in the pump (that is 

 the calculated weight of the water), the friction of the pit work, and 

 the friction of the engine itself. 



The calculations most relied on referred to a large engine, the press- 

 ure of whose steam had been ascertained by an excellent indicator 

 from the North of England. 



Joseph T. Price of Neath Abbey exhibited the model of a pair of 

 paddle-wheels which he had fixed on the Lord Beresford steamer at 

 Southampton, in substitution of a pair of ordinary wheels. 



It has an eccentric wheel fixed to the side of the vessel, in which a 

 band is placed, having rods leading to cranks on each paddle iron; these 

 have each an axis, and hence as the engine moves the shaft and its pad- 

 dle arms, the eccentric with its rods and cranks produces a motion which 

 ensures the nearly vertical insertion of the paddle board or irons into 

 the water, and when lifting turn it in like manner nearly vertically, 

 hereby avoiding the pernicious effects of Ordinary paddles, when from 

 any cause they happen to be wading in water beyond the limit allotted 

 them in smooth water, with the ship in exact trim. 



The effect J. T. Price described to be great relief to the engine, in 

 so much that about two thirds the coal would produce an effect in the 

 speed of the vessel, otherwise under equal circumstances, equivalent to 

 her former speed, by cutting off part of the steam equal to the reduced 

 resistance of the paddles in the water. The objection to these paddles 

 J. T. Price fully admitted to lie in the additional liability to require 

 repair, and the consequent need of attention ; but he resolved this into 

 a simple question of expense, and assuming that it might cost 1 00/ per 

 annum more to maintain these than the ordinary paddles, which if all 

 needful spare articles were constantly kept ready, he contended would 

 suffice for a pair of forty-horse engines (say eighty-horse power), there 

 appeared to him a clear advantage in their favour in the oeconomy of fuel 

 or in accelerating the voyages to be performed by the vessel employing 

 them. 



Mr. GowEU described the nature and construction of the boiler used 

 in the steam-packet Vesta, the bottom of which is covered to a small 

 depth with mercury, for the purpose of equalizing the distribution of 

 heat, and regulating the evolution of steam. 



K 2 



