thus discharged, I cannot but conceive that a _number_ of such
conductors must considerably lessen that of any approaching cloud,
before it comes so near as to deliver its contents in a general
stroke:--An effect not to be expected from bars _unpointed_; if the
above experiment with the blunt end of the wire is deemed pertinent
to the case.
The pointed wire under the prime conductor continuing of the same
height, _pinch_ it between the thumb and finger near the top, so as
_just to conceal_ the point; then turning the globe, the electrometer
will rise and mark the full charge. Slip the fingers down so as to
discover about half an inch of the wire, then another half inch, and
then another; at every one of these motions _discovering more and
more_ of the pointed wire; you will see the electrometer fall quick
and proportionably, stopping when you stop. If you slip down the
_whole distance_ at once, the ball falls instantly down to the stem.
From this experiment it seems that a greater effect in drawing off
the lightning from the clouds may be expected from _long_ pointed
rods, than from _short_ ones; I mean from such as show the greatest
length, _above the building_ they are fixed on.
Instead of pinching the point between the thumb and finger, as in
the last experiment, keep the thumb and finger each at _near an inch
distance_ from it, but at the _same height_, the point between them.
In this situation, though the point is fairly exposed to the prime
conductor, it has little or no effect; the electrometer rises to
the height of a full charge.--But the moment the fingers are _taken
away_, the ball falls quick to the stem.
To explain this, it is supposed, that one reason of the sudden effect
produced by a long naked pointed wire is, that (by the repulsive
power of the positive charge in the prime conductor) the natural
quantity of electricity contained in the pointed wire is driven down
into the earth, and the point of the wire made strongly _negative_;
whence it attracts the electricity of the prime conductor more
strongly than bodies in their natural state would do; the _small
quantity of common matter_ in the point, not being able by its
attractive force to retain its _natural quantity of the electric
fluid_, against the force of that repulsion.--But the finger and
thumb being substantial and blunt bodies, though as near the prime
conductor, hold up better their _own_ natural quantity against the
force of that repulsion; and so, continuing nearly in the natural
_Just Published_, A GRAMMATICAL CATECHISM for the use of Schools, upon the plan of Lindley Murray.Page 1
half bound 1 0 Wonders of the Horse, recorded in Anecdotes, Prose and Verse, by Joseph Taylor 2 6 Tales of the Robin & other Small Birds, in Verse, by Joseph Taylor 2 6 Instructive Conversation Cards, consisting .Page 2
The hour of the sale not being come, they were conversing on the badness of the times; and one of the company called to a plain, clean, old man, with white locks, 'Pray, Father Abraham, what think you of the times? Will not those heavy taxes quite ruin the country! How shall we be ever able to pay them? What would you advise us to?'----Father Abraham stood up, and replied, 'If you would have my advice, I will give it you in short; "for a word to the wise is enough," as Poor Richard says.Page 3
" Work while it is called to-day, for you know not how much you may be hindered to-morrow.Page 4
" [Illustration: Published by W.Page 5
Darton, Junr.Page 6
got together to this sale of fineries and nick-nacks.Page 7
But poverty often deprives a man of all spirit and virtue.Page 8
Remember, Job suffered, and was afterwards prosperous.Page 9
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