228 Mr. Read's Meteorological Journal 
of the other hand touch a sensible electrometer, and if the 
threads open, it is sufficient. But should the electrical state 
of the atmosphere be too weak to produce that effect, which 
seldom happens, then in that case I add to the rod a lighted 
torch T, and place it as remote from my hand as the strength 
of the rod will bear, and repeat the experiment ; thus cir- 
cumstanced, it has never yet failed me. 
It will be necessary just to mention the method I have 
pursued in forming the journal of atmospherical electricity. 
This has been principally by means of the signs exhibited by 
the pith balls O, connected with the rod. When I find these 
closed, and attracted on the approach of my linger, yet not 
sufficiently charged to repel each other, I write weak signs 
of electricity. When I find the balls open, and, on the ap- 
proach of excited glass, the balls close, I write they are elec- 
trified positively ; but, if the balls open wider, I write they 
are electrified negatively ; and the reverse when I use sealing- 
wax. When the balls diverge one inch and upwards, visible 
sparks may be drawn at the brass ball N. When sparks 
are said to have been perceived in any observation, I have ge- 
nerally on that account omitted to note the variable quan- 
tities of divergency in the pith balls. Their utmost limit of 
regular divergency seems to be about five or near six inches ; 
above that they are unsteady and disorderly. The pith balls 
are near two-tenths of an inch in diameter, suspended by very 
fine flaxen threads (in the state it is in from the heckle) five 
inches long. When I mention the distance of the balls in 
tenths of an inch, it is to be understood as nearly so as my 
eye can determine. 
This apparatus requires a constant attention, especially 
