KBW cngihe. Ijy 



the iflomentum of the moving power. The remainder 

 serves to raise a weight of twelve pounds with a uniform ve- 

 locity of an inch in a second : that is to say, the machine 

 continually winds up itself, and leaves a disposable power, 

 equal to four times what would be necessary in an external 

 agent to keep the machine in motion. 



It follows from what has been said, that, in the machine 

 of Mr. Cai^niard, the heat at least quintuples the volume of 

 air employed in it; since it is evident, that the effect pro- 

 duced must be proportional to the volume of this air dilated. 

 I have said at least, on account of the faction to be over- The fHction 

 come: but this friction is very trifling, because both the ^^""y *"^'"8» 

 screw and the wheel, being immersed in water, lose a con- 

 siderable portion of their weight, and consequently press 

 very little on their pivots. Besides, the movements are slow, 

 and not alternative, and there is no jerk in them ; so that this 

 machine is free from those resistances, that commonly con- and wear but 

 sume great part of themoving power in others, and accele- s^nall* 

 rate their wear. 



We do not look upon the machine of Mr. Cagniard as It may be use- 

 art object of curiosity merely: it may be useful under |JJ ^^'JjJJj^^^g'Jj *, 

 various circumstances. As it produces its effeft in a body ations. 

 of water heated only to 75° [l67°F.], or even less, it affords 

 an opportunity of turning to account the hot water, that in 

 various manufiictories is thrown away, or runs to waste, in 

 saltworks, for instance, the ebullition of the saline solution 

 might be made, by means of Mr. Cagniard''^ machine, to 

 work the pumps for filling the boilers : in ironworks the heat' 

 of the furnace might be made to work the bellows : in com- 

 mon steam-engines, which, like that at Chaillot, furnish 

 a large quantity of very hot water, an action might be ob- 

 tained equivalent to that of several men, or horses: in fin^^ 

 in baths, distilleries, potteries, limekjilns, glasshouses, foun- 

 deries, and wherever there is a production of hot water, or 

 of heat, advantage might be made of Mr. Cagniard's nitf^ 

 chine. This machine, which, as has been said, is liable to 

 very little friction or want of repair, has also the advantagie*^ 

 of being easily managed ; and when its action is suspended 

 for a time without extinguishing the fire, the beat is not 



Vol; XXiX.-.JuLr, 1811. If' lo«: 



