r elating to Atmospherical Electricity. 227 
S is a small table fixed to the wall under the bell and ball, 
at a convenient height above the floor, upon which Leyden 
bottles and other apparatus are occasionally placed. Any 
person versed in the science of electricity, will easily under- 
stand that this apparatus is calculated to show the various de- 
grees of intensity of atmospherical electricity ; and at the same 
time to avoid the pernicious effects which may be occasioned 
by thunder-storms, or in short by any great quantity of elec- 
tricity in the atmosphere. 
The whole perpendicular height of both parts of this appa- 
ratus taken together, from the moist earth to the point at 
the top of the rod, is 61 feet. If the insulation could be con- 
stantly kept in due temperature, with respect to heat and 
cold, I imagine it would always be electrified. But I fear that 
cannot be done, without the aid of common fire ; which in 
so large an apparatus would be very difficult, so that there 
might not be too much nor too little of it. I am inclined to 
this opinion, from the success I have had in a number of ex- 
periments, in which the aid of common fire was applied to 
improve the insulation, as well as to collect the electric fluid. 
When I find that the moisture in the air has so much in- 
jured the insulation of my high pointed rod, that it will not 
retain a weak electricity, in that case I make use of my 
hand exploring rod, which is about the length and thickness 
of a common fishing-rod, with plenty of small wire twined 
round it from end to end. The method of using it is simple 
and easy. A representation of it may be distinctly seen in 
fig. 2. Having first warmed the glass legs of the stool, I 
place myself upon it, and raise the rod into a vertical posi- 
tion, keeping it so for a minute or two ; I then with a finger 
