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to the earth; but sometimes, on the contrary, from the earth, buildings, and other eminences, to the clouds. For the principle upon which its direction depends, appears to arise from the restoration of a certain equilibrium, in a subtile and elastic fluid, previously disturbed by various causes.
Now, according to the laws of elastic fluids, the endeavour to restore the equilibrium of such a fluid, will be in that direction, where the resistance to it's passage happens to be the least. Upon this principle we therefore see a necessity, either to open a passage for it to go freely through, by placing certain bars of metal properly; or, to stop the passage of the fluid through such buildings entirely.
The last method would be dangerous to put in practice; because, if high buildings were so secured, the lightening would then attack the lower buildings, which are far more numerous, and probably would destroy a greater number of people, cattle, &c.
Whereas, if the first method is preferred, the high buildings will then tend to protect the lower ones more effectually; and may with propriety be considered, as so many pipes to carry off the lightening quietly; either from the earth to the clouds, or from the clouds to the earth.
And that several proper conductors are necessary to carry off the lightning more readily, than some of the accidental or partial conductors, in a large town, are capable of, appears from this; that we are able to collect small quantities of the electric fluid, with a slender apparatus in our hands only; whilst it is exposed in the street, garden, or other open place, during the hovering of such clouds as occasion violent lightening.
