372 On the Heat developed in Combustion 



bent horizontally, so as to pass three times from one 

 end of the receiver to the other, and is supported in its 

 place, two lines above the bottom of the receiver, by 

 several little feet. 



The aperture that forms the mouth of the worm is 

 a circular hole in its bottom, near its broadest end. 

 Into this hole is soldered a perpendicular tube, an inch 

 in length and an inch in diameter, reaching within the 

 worm to the height of a quarter of an inch above its 

 bottom. 



This tube passes through a circular hole in the bot- 

 tom of the receiver, to which also it is soldered. Its 

 lower aperture is seven lines below the bottom of the 

 receiver ; and through this the products of the combus- 

 tion enter into the worm. 



The other extremity of the worm passes horizontally 

 through the perpendicular end of the receiver, opposite 

 to that near which the products of the combustion enter 

 the worm. 



The worm, before it passes through the end of the 

 receiver, is fashioned into the shape of a round pipe, 

 half an inch in diameter ; and an inch in length of this 

 pipe is seen without the receiver. This piece is made 

 to fit tight into another similar tube, belonging to the 

 worm of another receiver, which I call the secondary 

 receiver ; the purpose of which is to receive the heat 

 that might still be found in the products of combustion, 

 after they have passed through the worm of the prin- 

 cipal receiver. 



To support these two receivers in the air, so as not 

 to touch the table that supports them, each of them is 

 fixed in a frame of dry linden wood, made of rods an 

 inch square. Round the bottom of each receiver is a 



