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N. B. I keep my tube fufpended 

 limply upon a brafs ring, foldered 

 a little way within the brafs tube, 

 which does very well. 



Fig. VI. That part of the under- 

 piece of the brafs fcale by which it 

 is fupported upon the gingle. 



Fig. VII. The wooden- trough 

 full of water, in which the whole 

 apparatus is ufed. This trough 

 ought to be (in the infide) 2 feet 

 long, 1 3 inches deep, and 1 7 inches 

 wide. The board a, upon which 

 the jars, Sec. are placed, ought to 

 be fixed at the diftance of 3| inches 

 from the brim ; the length of the 

 board ought to be about 9 inches, 

 the thicknefs of it two inches. 

 The trough ought to be kept full 



of 



