I 2^1 ] 



A is an oblong trough, about eight inches 

 deep, kept nearly full of water, and B, B are jars 

 {landing in it, about ten inches long, and two and 

 a half wide ; fuch as I have generally ufed for 

 electrical batteries. 



C, C are flat {tones, funk about an inch, or half 

 an inch, under the water, on which veiTels of any 

 kind may be conveniently placed, during a courfb 

 of experiments. 



D, T> are pots nearly full of water, in which 

 jars or phials, containing any kind of air, to which 

 plants or any other fubflances may be expofed, 

 and having their mouths immerfed in water ; fo 

 that the air in the infide can "have no communication 

 with the external air. 



E is a fmall glafs veffel, of a convenient fize for 

 putting -a moufe into it, in order to try the whole- 

 ibmenefs of any kind of air that it may contain. 



F is a cylindrical glafs Vefiel, five inches in length, 

 and one in diameter, very proper for trying whe- 

 ther any kind of air will admit a candle to burn 

 in it. For this purpofe a bit of wax candle, G, 

 may be fattened to the end of a wire, H, and 

 turned up in fuch a manner as to be let down into 

 the veflel with the flame upwards. The verTel 

 mould be kept carefully covered till the moment 

 that the candle is admitted to it. In this manner 

 1 have frequently extinguifhed a candle above 

 -twenty times in one of thefe veflels full of air, 

 though it^ is impoffible to dip the candle into it, 

 without giving the external air an opportunity of 

 •mixing with it, more or lefs. 



Kka lis 



