, that such catastrophes as those described
could never occur, if the imperfect conductors of which our buildings
are generally composed, were encompassed by more perfect conductors.
The ridge of the roof of every house should be of metal; and, if that
metallic ridge were connected with the leaden water-pipes, and by them
continued into the ground, all buildings would be protected. A
descending or an ascending ball would then find a conduit, by which to
pass, or freely propagate its powers, without the violent effects that
accompany its transition through air and other non-conductors. The
rods of Franklin are toys, which were ingeniously contrived in the
infancy of this branch of science, but they ought now to be forgotten.

Before I dismiss this interesting topic, I would ask whether the
transmission of the power called _electric_, to a particular spot,
does not always afford evidence, that at that spot there exists,
beneath the surface of the earth, either a vein of metallic ore, a
spring, or some other competent conductor, which the power called
_electric_ is seeking to reach, when the antagonist non-conductors
exhibit their destructive phenomena? Does not the power or vacuum
created by the change of volume in the aqueous vapour of the cloud,
regard only the perfect conductors prepared to receive it, however
deeply they may be concealed beneath the surface of the non-conducting
or imperfectly-conducting soil and vegetable surface? If it were not
so, would not the stroke always affect the higher objects, or prefer
palpable conductors in moderately elevated sites? In this instance 200
degrees of the horizon were more elevated than the place attacked,
while the destruction proves that the superficies invited no
accumulation here. Must not then the predisposing and operative cause
have existed beneath the surface; and, hence, may not the selection of
lightning, in most cases where it prefers lower sites, afford evidence
of the existence of metallic strata, of springs, or other conducting
surfaces, the discovery of which, by such natural test, may sometimes
be important to the owner of the soil?

The bottom of Roehampton-lane joins the road which leads from Putney
and Wandsworth to Richmond. Here I came again upon the same alluvial
Flat which I left when I ascended from Wandsworth to Putney-heath,
having since passed a corner of the undulating high land on which
stand Wimbledon, its common, Roehampton, Richmond-park, and