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<ulC but fometimes, on the contrary, from 
the earth, buildings, and other eminences, to the 
clouds. For the principle upon which its direction 
depends, appears to arife from the reftoration of a 
certain equilibrium , in a fubtile and elaflic fluid, pre- 
vioufly diflurbed by various caufes. 
Now, according to the laws of elaflic fluids, the 
endeavour to reflore the equilibrium of fuch a fluid, 
wifl be in that diredion, where the rejijlance to it’s 
paflage happens to be the leaft. Upon ‘this principle 
we therefore fee a neceflity, either to open a paflage 
for it to go freely through, by placing certain bars of 
metal properly j or, to flop the paflage of the fluid 
through fuch buildings entirely. 
The lafl method would be dangerous to put in 
pradice ; becaufe, if high buildings were fo fecured, 
the lightening would then attack the lower buildings* 
which are far more numerous, and probably would 
deftroy a greater number of people, cattle, &c. 
Whereas, if the firft method is preferred, the high 
buildings will then tend to proted the lower ones 
more efledually ; and may with propriety be confl- 
dered, as fo many pipes to carry off the lightening 
quietly j either from the earth to the clouds, ° or from 
the clouds to the earth. 
And that feveral proper condudors are neceflary to 
carry off the lightning more readily, than fome of 
tne accidental or partial condudors, in a large town, 
are capable of, appears from this j that we are able to 
colled fmall quantities of the eledric fluid, with a 
flender apparatus in our hands only; whilft it is ex- 
pofed in the flreet, garden, or other open place, dur- 
ing the hovering of fuch clouds as occafion violent 
lightening. 
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