The Massachusetts spy, and Worcester County advertiser. [volume] ([Worcester, Mass.]) 1825-1831, 1825-08-17

into the earth yet, conceive that the chief
utility Of the lightning rod consists, not in con-
Quoting to place of safety an exploded mass
Of fluid, but in preventing the explosion alto
gether.
4th. Is it not Objectionable TO have the
stem Of lightning rod ascend beside Of, and
adhere TO, chimnies-and what philosophical
objection could be raised TO the rods being
perpendicularly erected at small distance
from the end of the house, having at the bot
tom some sufficient supporter of wood, and moi
come in contact with the house at all :"
The only objection there can be TO having
the rod erected beside Of, and adhering to, the
chimney is, that, in that situation, its points
are liable to become coated with the light SUBJ
stances that are constantly ascending from the
burning fuel below. This coating, at least
when dry, must he a non-conductor, and the
points, being covered over with this substance,
will, of course, lose their natural attraction
or power of receiving the fluid. Hence the
good effects anticipated of the conductor will
never be realized, when thus coated.-The
only observations would make, with regard
to erecting the rod at short distance from
the house, is, there evidently being certain
sphere of influence, and this very limited, in
WHiSu litC IOu (dn noNC entity tJ'
farther it is removed from the house, or might
say, from the centre Of The roof, the less effec-
tual will it be in preserving it.
omit answering the 9Th query Of your cor
respondent, leaving that for the inventive
powers of the mechanic, only suggesting, that
small block of hard wood, with hole for
the rod to pass through it, might easily be fit
ted to the top of the building, and there fasten-
ed, which would answer for supporter, and
yet not have the appearance 6 of human
skeleton standing on the ridge-pole'' TO fright
en- the passers by.
Having attended to the queries Of your cor
respondent, will now mention one alteration
in the construction of the lightning rod which
have never yet seen noticed by any writer,
viz. not only to have the elevated end Of the
rod terminate in points, but also that which
is inserted in the ground. Experiment proves,
as above limited, that points not only receive,
but suffer electricityto pass off much more read
lily than body with blunted end, or knob.
Such being the case then, the elevated points,
(supposing the clouds to be always positively
electrifed) will receive the fluid faster than 1T
can pass off into the. earth. Have not evils
arisen from this very circumstance. The points
attracting and receiving the electricity faster
than it is conducted of, thus. charge the rod
with a greater quantity than it can contain
the attraction continues to draw the electrical
matter together, till finally an explosion is
produced, which might have been prevented,
provided the lower end of the rod had been
pointed.
But furthermore, experiments made by DIR.
franklin and others, prove that the clouds are
often negatively, and the earth positively cleo
tri6ed. And Franklin observed that the light
ming as often struck from the earth to the
clouds, as from the clouds to the earth. In
such cases, we wish to conduct the fluid from
The earth 10 the clouds The same reasoning
then that goes to prove the utility of elevated
points, will also prove the utility Of having
the rod terminate in the same manner at the
lower end. Besides, if points will suffer the
fluid to pass off much more readily, would not
rod of half the usual diameter, when point
ed at both ends, be as effectual as larger one,
pointed only at one end?
might continue my observation upon this
highly interesting and useful subject to much
greater length; but forbear, hoping that some
more experienced persons may employ their
pens to inform the public.
PHILO PHILOSOPHER.