24 
Mr. Harris on the relative powers^ ^c. 
EXPLANATION OF PLATE 11 . 
abed The glass bulb. 
ab The wire. 
d The brass caps and screws which unite the ball to the 
glass cup. 
e The glass cup. 
c A small valve. 
ab The flanches and balls. 
gfe The glass tube. 
gf The scale. 
s The stand. 
Pa. 6N The connecting wires. 
