VOL. XLIX.] PHILOSOPHICAL TRANSACTIONS. 6Q5 



singular use, if it could be applied in the fire-engine. The great expence of 

 large boilers in the construction of that machine, and the vast consumption of 

 fuel in the working of it, render its uses much less extensive than they would 

 be, could those expences be contracted. But air cannot be applied in this en- 

 gine, to increase the quantity of the elastic steam, since it would pass with the 

 steam from the boiler into the cylinder, and prevent a vacuum from being there 

 produced, and hinder the piston from moving in it. 



A mechanical agitation of the water in the boiler of the fire-engine mav how- 

 ever be produced by other means, so as that a larger quantity of steam may pro 

 bably be raised, than can be effected in engines as commonly now constructed ; 

 by which means the expences of constructing and working those useful machines 

 may perhaps be greatly lessened. 



If, for example, the boiling water, instead of being agitated by air, as in Dr. 

 Hales's method, was briskly stirred about by a wheel placed in the boiler of the 

 fire-engine ; it is probable, that by this means the quantity of elastic vapour 

 raised might be considerably increased, and less fuel and a less boiler might then 

 serve the purpose. The wheel might be turned round by the water drawn up 

 by the engine ; or might receive its motion fi-om the beam of the engine by 

 means of a crank ; or a labourer might be employed in turning it round with 

 the hand. 



But the desired effect might, in all probability, be better produced by means 

 of elastic steam driven briskly through the boiling water. The steam of water, 

 as an elastic fluid, possesses many of the properties of common air. Like air, 

 when driven briskly from the aeolipile, it is observed to blow up fire ; and when 

 forcibly driven through water, will doubtless produce the same agitation, as is 

 done by common air in Dr. Hales's experiment ; and may probably have the 

 like effect with air, in elevating a larger quantity of elastic vapours. In order to 

 excite an agitation in the boiling water of a fire-engine, by means of elastic steam. 

 Dr. B. then proposes various means for this end. He also shows how the steam 

 from the boiler of such an engine may be greatly increased in its strength, by 

 heating it, by causing some part of the pipe that conveys it from the boiler to 

 the cylinder, to be kept red hot, by making it pass through a fire. 



LXXVI. Of an Extraordinary Motion in the fVaters in the Lake Ontario in 

 North- America. From Governor Belcher's Lady; dated Elizabeth-town, 

 New-Jersey, Oct. 12, 1755. p. 544. 



I take this opportunity to acquaint you with a strange phenomenon of the 

 lake Ontario, where general Shirley has posted himself with 2000 men, at fort 

 Oswego. A person lately come from the camp reports, that about a fortnight 



