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To make the experiment in queftion, it is neccf- 
fary that bodies fhould be fupported by glafs, filk, 
or refin, without touching any thing elfe commu- 
nicating with what we now call non-ele£trics ; with- 
out which, the figns of electricity, which are fought 
tor, cannot manifeft themfelves. 
To this experiment, therefore, a previous know- 
lege is required, of infulating bodies to be eleCtrifedy 
but where is the man who was acquainted with this 
faCt thirty years ago ? Before that period, it was not 
even gueffed at by any one. 
Since Mr. Gray difcovered, that bodies mufl be in- 
fulated, to communicate to them a perceptible eleCtric 
virtue, to what purpofe could we fet up iron bars 
under a ftormy cloud ? This thought could not have 
happened, but to thofe who had taken notice of the 
analogy between lightning and electricity, and upon 
whom this idea had made a ftrong impreffion. And 
no one could think ferioufly upon this analogy, but 
tince the difcovery of the experiment of Leyden, that 
is, fince the year 1 746. Before that time the eleCtrifa- 
tion of bodies by thunder could not have been per- 
ceived, but by an accident very difficult to meet, on 
account of the conditions requifite. 
Neverthelefs it may be urged, that bodies, being 
really eleCtrifed, have fhewn themfelves in all ages*, 
as 
* I formerly took notice, that the eleilrical attra£fion had been 
obfervtd fo early, as to be mentioned by Theophraftus (fee Phil, 
Tranf. Vol. XLIV. p. 732) ; fo its luminous appearance, though 
only confidered as a meteor, is mentioned by Plutarch, in the life 
of Lyfander. Pliny, in the fecond book of his natural hiflory, chap. 
5 37 - 
