LIGHTNING. 
phers had not proceeded far in their expe- 
riments and inquiries on this subject, before 
they perceived the obvious analogy between 
lightning and electricity, and they pro- 
duced many arguments to evince tlieii- simi- 
larity. But the method of proving this 
hypothesis, beyond a doubt, was first pro- 
posed by Dr. Franklin, who, about the ' 
close of the year 1749, conceived the prac- 
ticability of drawing lightning down from 
the clouds. Various circumstances of re- 
semblance between lightning and electri- 
city were remarked by this philosopher, 
and have been abundantly confirmed by 
later discoveries, such as the following: 
Flashes of lightning are usually seen crooked 
and waving in the air; so the electric 
spark drawn from an irregular body at 
some distance, and when it is drawn by an 
irregular body, or through a space in which 
the best conductors are disposed in an irre- 
gular manner, always exhibits the same ap- 
pearance. Lightning strikes the highest 
and most pointed objects in its course, ip 
preference to others, as hills, trees, spires, 
masts of ships, &c. so all pointed conduc- 
tors receive and throw off the electric fluid 
more readily than those that are terminated 
by flat surfaces. Lightning is observed to 
take and follow the readiest and best con- 
ductor ; and the same is the case with elec- 
tricity in the discharge of the Leyden phial ; 
from whence the Doctor infers, that in a 
thunder-storm it would be safer to have 
one’s clothes wet than dry. Lightning 
burns, dissolves metals, rends some bodies, 
sometimes strikes persons blind, destroys 
animal life, deprives magnets of their virtue, 
or reverses their poles ; and all these are 
well-known properties of electricity. 
To demonstrate, however, by actual ex- 
periment, the identity of the electric fluid 
with the matter of lightning, Dr. Franklin 
eontrived to bring lightning from the hea- 
vens by means of a paper kite, properly 
fitted up for the purpose, with a long fine 
wire string, and cajled an electrical kite, 
which he raised when a thunder storm was 
perceived to be coming on: and with the 
electricity thus obtained, he charged phials, 
kindled spirits, and performed all other 
such electrical experiments as are usually 
exhibited by an excited glass globe or cy- 
linder. This happened in June, 1752, a 
month after the electricians in France, in 
pursuance of the method which he had be- 
fore proposed, had verified the same theory, 
but without any knowledge of what they 
had done. The most active of these were 
Messrs. Dalibard and Delor, followed by 
M. Mazeas, and M. Monnier. 
Nor had the English philosophers been 
inattentive to this subject. Mr. Canton, 
however, succeeded in July, 1752; and in 
the following month Dr. Bevis and Mr. 
Wilson observed nearly the same appear- 
ances as Mr. Canton had done before. By a 
number of experiments, Mr. Canton also 
soon after observed, that some clouds were 
in a positive, while some were in a negative 
state of electricity; and that the electricity 
of his conductor would sometimes change 
from one state to the other five or six times 
in less than half an hour. 
How it happens that particular parts of 
the earth, or the clouds, come into the op- 
posite states of positive and negative elec- 
tricity, is a question not absolutely deter- 
mined : though it is easy to conceive that 
when particular clouds, or different parts of 
the earth, possess opposite electricities, a 
discharge will take place within a certain 
distance; or the one will strike into the 
other, and in the discharge a flash of 
lightning will be seen. Mr. Canton queries 
whether the clouds do not become possessed 
of electricity by the gradual heating and 
cooling of the air; and whether air suddenly 
rarefied may not give electric fire to clouds, 
and vapours passing through it, and air 
suddenly condensed receive electric fire 
from them. Mr. Wilcke supposes, that the 
air contracts its electricity in the same man- 
ner that sulphur and other substances do, 
when they are heated and cooled in contact 
with various bodies. Thus, the air being 
heated or cooled near the earth, gives elec- 
tricity to the earth, or receives it from it; ; 
and the electrified air being conveyed up- 
wards by various means, communicates its 
electricity to the clouds. Others have que- 
ried, whether, since thunder commonly 
happens in a sultry state of the air, when it 
seems charged with sulphureous vapours, 
the electric matter then in the clouds may 
not be generated by the fermentation of 
sulphureous vapours with mineral or acid 
vapours in the air. With regard to places 
of safety in times of thunder and lightning. 
Dr. Franklin’s advice is, to sit in the middle 
of a room, provided it be not under a metal 
lustre suspended by a chain, sitting on one 
chair, and laying the feet on another. It is 
still better, he says, to bring two or three 
mattresses, or beds, into the middle of the 
room, and folding them double, to place 
the chairs upon them ; for as they are not 
so good conductors as the walls, the light- 
