226 Mr. Read's Meteorological Journal 
electric fluid, one of them is twisted round the rod to the 
right hand, and the other to the left, as low down as the brass 
collar H, to which they are soldered, in order to render their 
contact perfect. A little above the upper end of the glass 
pillar B, is placed a brace II of solid glass sticks, to keep 
steady that part of the rod. K is a hollow cylinder of wood, 
12 inches within, proceeding from the ceiling through the roof 
LL, above which there is a hollow tin cover M, 24 inches 
within, fixed to the rod ; which serves to defend the open cy- 
linder K from the weather. At a convenient distance from 
the foot of the rod is a hole bored through the floor and ceil- 
ing. This hole receives a glass tube covered with sealing- 
wax (as are all the other glasses in this apparatus), through 
which a strong brass wire proceeding from the rod is con- 
veyed into the room below, wherein, at a convenient height 
from the floor, it terminates with a two-inch brass ball N. 
A strong ring of brass is made to move easy on the wire, and 
rests on the brass ball ; into this ring is screwed a brass wire 
seven inches long, which keeps suspended at its extremity a 
pith-ball electrometer O. 
At two inches distance of the above-mentioned brass ball 
N, a bell P is supported by a strong wire, which passing 
through a hole made in the wall, is made to communicate, by 
means of a good metallic continuation Q, with the moist 
ground adjoining to the house. A brass ball, three-tenths of 
an inch in diameter, is suspended between the bell P and ball 
N, by a silk thread fastened to a nail R. This ball serves for 
a clapper, by striking between the ball and bell, when the 
electrical charge of the rod is sufficiently strong. V gives 
nearly a front view of this part of the apparatus. 
