■ r 



N 



35^ 



MISCELLANEOUS PAPERS. 



leaving a fpace between to contain air. The top or cover 

 is brazed on, and the whole made air-tight. Through 

 the top IS inferted a brafs cock, and alfo a brafs or copper 

 cylinder, open at both ends, about two inches and a quar- 

 ter in diameter, and two feet long, fo fixed as to rife four- 

 teen inches above the top, and to reach near to the bottom 



of the veffeh 



Through the fide of the innermoft vcifel, near the top, 



are fome holes made, whereby the air in the cavity be- 

 tween the two bottoms and fides may communicate with 

 the air in the infide of the veilel. 



4. Z), A phial two inches diameter, and (even inches 

 deep, corked and fealed, with a hook fixed in the cork, 

 by which the phial is fufpended. 



Thefe are the principal parts of the machine, which are 



to be applied as follows. 



From the furface let there be an horizontal flue, of a 

 convenient length. In the walls of the flue, the frame, 

 in which the regifter Aides, is fixed perpendicularly, fo 

 that when the regifter is down, the flue is clofed, when 

 the regifter is drawn up, the flue is opened, and the higher 

 it is raifed, the more is the paflage of the fire enlarged. 



To the ihorter end of |he balance, which is fupported 

 on a proper fulcrum,, at a convenient heighth, the regifter 

 is fufpended by a chain and a rod; the chain is juft long 

 enough to wind over the fegment of the circle, at the end 



of the beam. The regifter is ma<le fo heavy, as to de- 



fcend by its own weight. 



At the diftance of two, three, or more feet from the 

 rep-ifter, and on the flue of the furface, the copper veflel 

 C is fixed, fo as to receive a heat from the fire paffing 

 through the flue. The end of the longeft arm of the 

 balance extends dircdly over the cylinder fixed in the cop- 



and to it the phial D is fufpended, fo as to hang 







pe 



ube 



will allow it to be about two or three inches immerfed in 

 the tube, when the balance is in cquilibrio. On the fime 



end 



