Non-electric bodies, that have electric fire thrown into them, will
retain it till other electrics, that have less, approach; and then it
is communicated by a snap, and becomes equally divided.
2. Electrical fire loves water, is strongly attracted by it, and they
can subsist together.
3. Air is an electric _per se_, and when dry will not conduct the
electrical fire; it will neither receive it, nor give it to other
bodies: otherwise no body surrounded by air, could be electrified
positively and negatively: for should it be attempted positively, the
air would immediately take away the overplus; or negatively, the air
would supply what was wanting.
4. Water being electrified, the vapours arising from it will be
equally electrified; and floating in the air, in the form of clouds,
or otherwise, will retain that quantity of electrical fire, till they
meet with other clouds or bodies not so much electrified, and then
will communicate as before-mentioned.
5. Every particle of matter electrified is repelled by every other
particle equally electrified. Thus the stream of a fountain,
naturally dense and continual, when electrified, will separate and
spread in the form of a brush, every drop endeavouring to recede from
every other drop. But on taking out the electrical fire they close
again.
6. Water being strongly electrified (as well as when heated by common
fire) rises in vapours more copiously; the attraction of cohesion
among its particles being greatly weakened, by the opposite power of
repulsion introduced with the electrical fire; and when any particle
is by any means disengaged, it is immediately repelled, and so flies
into the air.
7. Particles happening to be situated as _A_ and _B_, (FIG. VI.
_representing the profile of a vessel of water_) are more easily
disengaged than _C_ and _D_, as each is held by contact with three
only, whereas _C_ and _D_ are each in contact with nine. When the
surface of the water has the least motion, particles are continually
pushed into the situation represented by _A_ and _B_.
8. Friction between a non-electric and an electric _per se_ will
produce electrical fire; not by _creating_, but _collecting_ it:
for it is equally diffused in our walls, floors, earth, and the
whole mass of common matter. Thus the whirling glass globe, during
its friction against the cushion, draws fire from the cushion, the
cushion is supplied from the frame of the machine, that from the
floor on which it stands. Cut off the communication by thick glass or
wax, placed under the cushion, and no fire can be _produced_, because
it cannot be _collected_.
9. The ocean is a compound of water, a non-electric, and salt an
electric _per se_.
10. When there is a friction among the parts near its surface, the
electrical fire is collected from the parts below. It is then plainly
visible in the night; it appears in the stern and in the wake of
every sailing vessel; every dash of an oar shews it, and every surf
and spray: in storms the whole sea seems on fire.--The detached
particles of water then repelled from the electrified surface,
continually carry off the fire as it is collected; they rise and form
clouds, and those clouds are highly electrified, and retain the fire
till they have an opportunity of communicating it.
11. The particles of water, rising in vapours, attach themselves to
particles of air.
12. The particles of air are said to be hard, round, separate and
distant from each other; every particle strongly repelling every
other particle, whereby they recede from each other, as far as common
gravity will permit.
13. The space between any three particles, equally repelling each
other, will be an equilateral triangle.
14. In air compressed, these triangles are smaller; in rarified air
they are larger.
15. Common fire, joined with air, increases the repulsion, enlarges
the triangles, and thereby makes the air specifically lighter. Such
air, among denser air, will rise.
16. Common fire, as well as electrical fire, gives repulsion to the
particles of water, and destroys their attraction of cohesion; hence
common fire, as well as electrical fire, assists in raising vapours.
17. Particles of water, having no fire in them, mutually attract each
other. Three particles of water then, being attached to the three
particles of a triangle of air, would, by their mutual attraction
operating against the air's repulsion, shorten the sides and lessen
the triangle, whereby that portion of air made denser, would sink to
the earth with its water, and not rise to the formation of a cloud.
18. But if every particle of water attaching itself to air brings
with it a particle of common fire, the repulsion of the air being
assisted and strengthened by the fire, more than obstructed by the
mutual attraction of the particles of water, the triangle dilates,
and that portion of air, becoming rarer and specifically lighter,
rises.
19. If the particles of water bring electrical fire when they attach
themselves to air, the repulsion between the particles of water
electrified, joins with the natural repulsion of the air, to force
its particles to a greater distance, whereby the triangles are
dilated, and the air rises, carrying up with it the water.
20. If the particles of water bring with them portions of _both
sorts_ of fire, the repulsion of the particles of air is still more
strengthened and increased, and the triangles farther enlarged.
21. One particle of air may be surrounded by twelve particles of
water of equal size with itself, all in contact with it; and by more
added to those.
22. Particles of air, thus loaded, would be drawn nearer together by
the mutual attraction of the particles of water, did not the fire,
common or electrical, assist their repulsion.
23. If air, thus loaded, be compressed by adverse winds, or by being
driven against mountains, &c. or condensed by taking away the fire
that assisted it in expanding; the triangles contract, the air with
its water will descend as a dew; or, if the water surrounding one
particle of air comes in contact with the water surrounding another,
they coalesce and form a drop, and we have rain.
24. The sun supplies (or seems to supply) common fire to vapours,
whether raised from earth or sea.
25. Those vapours, which have both common and electrical fire in
them, are better supported than those which have only common fire in
them; for when vapours rise into the coldest region above the earth,
the cold will not diminish the electrical fire, if it doth the common.
26. Hence clouds, formed by vapours, raised from fresh waters within
land, from growing vegetables, moist earth, &c. more speedily and
easily deposite their water, having but little electrical fire to
repel and keep the particles separate. So that the greatest part of
the water raised from the land, is let fall on the land again; and
winds blowing from the land to the sea are dry; there being little
use for rain on the sea, and to rob the land of its moisture, in
order to rain on the sea, would not appear reasonable.
27. But clouds, formed by vapours raised from the sea, having both
fires, and particularly a great quantity of the electrical, support
their water strongly, raise it high, and being moved by winds, may
bring it over the middle of the broadest continent from the middle of
the widest ocean.
28. How these ocean clouds, so strongly supporting their water, are
made to deposite it on the land where it is wanted, is next to be
considered.
29. If they are driven by winds against mountains, those mountains
being less electrified attract them, and on contact take away their
electrical fire (and being cold, the common fire also;) hence the
particles close towards the mountains and towards each other. If the
air was not much loaded, it only falls in dews on the mountain tops
and sides, forms springs, and descends to the vales in rivulets,
which, united, make larger streams and rivers. If much loaded,
the electrical fire is at once taken from the whole cloud; and,
in leaving it, flashes brightly and cracks loudly; the particles
instantly coalescing for want of that fire, and falling in a heavy
shower.
30. When a ridge of mountains thus dams the clouds, and draws the
electrical fire from the cloud first approaching it; that which next
follows, when it comes near the first cloud, now deprived of its
fire, flashes into it, and begins to deposite its own water; the
first cloud again flashing into the mountains; the third approaching
cloud, and all succeeding ones, acting in the same manner as far back
as they extend, which may be over many hundred miles of country.
31. Hence the continual storms of rain, thunder, and lightning on
the east side of the Andes, which running north and south, and being
vastly high, intercept all the clouds brought against them from the
Atlantic ocean by the trade winds, and oblige them to deposite their
waters, by which the vast rivers Amazons, La Plata, and Oroonoko
are formed, which return the water into the same sea, after having
fertilized a country of very great extent.
32. If a country be plain, having no mountains to intercept the
electrified clouds, yet it is not without means to make them deposite
their water. For if an electrified cloud, coming from the sea,
meets in the air a cloud raised from the land, and therefore not
electrified; the first will flash its fire into the latter, and
thereby both clouds shall be made suddenly to deposite water.
33. The electrified particles of the first cloud close when they lose
their fire; the particles of the other clouds close in receiving
it: in both, they have thereby an opportunity of coalescing into
drops.--The concussion, or jerk given to the air, contributes also to
shake down the water, not only from those two clouds, but from others
near them. Hence the sudden fall of rain immediately after flashes of
lightning.
34. To shew this by an easy experiment: Take two round pieces of
pasteboard two inches diameter; from the centre and circumference of
each of them suspend by fine silk threads eighteen inches long, seven
small balls of wood, or seven peas equal in goodness: so will the
balls appending to each pasteboard, form equal equilateral triangles,
one ball being in the centre, and six at equal distances from that,
and from each other; and thus they represent particles of air.
Dip both sets in water, and some adhering to each ball, they will
represent air loaded. Dexterously electrify one set, and its ball
will repel each other to a greater distance, enlarging the triangles.
Could the water supported by seven balls come into contact, it would
form a drop or drops so heavy as to break the cohesion it had with
the balls, and so fall. Let the two sets then represent two clouds,
the one a sea cloud electrified, the other a land cloud. Bring them
within the sphere of attraction, and they will draw towards each
other, and you will see the separated balls close thus; the first
electrified ball that comes near an unelectrified ball by attraction
joins it, and gives it fire; instantly they separate, and each flies
to another ball of its own party, one to give, the other to receive
fire; and so it proceeds through both sets, but so quick as to be in
a manner instantaneous. In the cohesion they shake off and drop their
water, which represents rain.
35. Thus when sea and land clouds would pass at too great a distance
for the flash, they are attracted towards each other till within that
distance; for the sphere of electrical attraction is far beyond the
distance of flashing.
36. When a great number of clouds from the sea meet a number of
clouds raised from the land, the electrical flashes appear to strike
in different parts; and as the clouds are jostled and mixed by the
winds, or brought near by the electrical attraction, they continue
to give and receive flash after flash, till the electrical fire is
equally diffused.
37. When the gun-barrel, (in electrical experiments) has but little
electrical fire in it, you must approach it very near with your
knuckle before you can draw a spark. Give it more fire, and it will
give a spark at a greater distance. Two gun-barrels united, and as
highly electrified, will give a spark at a still greater distance.
But if two gun-barrels electrified will strike at two inches
distance, and make a loud snap, to what a great distance may 10,000
acres of electrified cloud strike and give its fire, and how loud
must be that crack?
38. It is a common thing to see clouds at different heights passing
different ways, which shews different currents of air one under the
other. As the air between the tropics is rarefied by the sun, it
rises, the denser northern and southern air pressing into its place.
The air so rarefied and forced up, passes northward and southward,
and must descend in the polar regions, if it has no opportunity
before, that the circulation may be carried on.
39. As currents of air, with the clouds therein, pass different ways,
it is easy to conceive how the clouds, passing over each other,
may attract each other, and so come near enough for the electrical
stroke. And also how electrical clouds may be carried within land
very far from the sea, before they have an opportunity to strike.
40. When the air, with its vapours raised from the ocean between
the tropics, comes to descend in the polar regions, and to be in
contact with the vapours arising there, the electrical fire they
brought begins to be communicated, and is seen in clear nights,
being first visible where it is first in motion, that is, where
the contact begins, or in the most northern part; from thence the
streams of light seem to shoot southerly, even up to the zenith of
northern countries. But though the light seems to shoot from the
north southerly, the progress of the fire is really from the south
northerly, its motion beginning in the north, being the reason that
it is there seen first.
For the electrical fire is never visible but when in motion, and
leaping from body to body, or from particle to particle through the
air. When it passes through dense bodies it is unseen. When a wire
makes part of the circle, in the explosion of the electrical phial,
the fire, though in great quantity, passes in the wire invisibly; but
in passing along a chain, it becomes visible as it leaps from link to
link. In passing along leaf gilding it is visible: for the leaf-gold
is full of pores; hold a leaf to the light and it appears like a
net, and the fire is seen in its leaping over the vacancies.--And as
when a long canal filled with still water is opened at one end, in
order to be discharged, the motion of the water begins first near
the opened end, and proceeds towards the close end, though the water
itself moves from the close towards the opened end: so the electrical
fire discharged into the polar regions, perhaps from a thousand
leagues length of vaporised air, appears first where it is first
in motion, _i. e._ in the most northern part, and the appearance
proceeds southward, though the fire really moves northward. This is
supposed to account for the _aurora borealis_.
41. When there is great heat on the land, in a particular region
(the sun having shone on it perhaps several days, while the
surrounding countries have been screened by clouds) the lower air is
rarefied and rises, the cooler denser air above descends; the clouds
in that air meet from all sides, and join over the heated place; and
if some are electrified, others not, lightning and thunder succeed,
and showers fall. Hence thunder-gusts after heats, and cool air after
gusts; the water and the clouds that bring it, coming from a higher
and therefore a cooler region.
42. An electrical spark, drawn from an irregular body at some
distance is scarcely ever strait, but shows crooked and waving in the
air. So do the flashes of lightning; the clouds being very irregular
bodies.
43. As electrified clouds pass over a country, high hills and high
trees, lofty towers, spires, masts of ships, chimneys, &c. as so many
prominencies and points, draw the electrical fire, and the whole
cloud discharges there.
44. Dangerous, therefore, is it to take shelter under a tree, during
a thunder-gust. It has been fatal to many, both men and beasts.
45. It is safer to be in the open field for another reason. When the
cloaths are wet, if a flash in its way to the ground should strike
your head, it may run in the water over the surface of your body;
whereas, if your cloaths were dry, it would go through the body,
because the blood and other humours, containing so much water, are
more ready conductors.
Hence a wet rat cannot be killed by the exploding electrical bottle,
when a dry rat may[45].
46. Common fire is in all bodies, more or less, as well as electrical
fire. Perhaps they may be different modifications of the same
element; or they may be different elements. The latter is by some
suspected.
47. If they are different things, yet they may and do subsist
together in the same body.
48. When electrical fire strikes through a body, it acts upon the
common fire contained in it, and puts that fire in motion; and if
there be a sufficient quantity of each kind of fire, the body will be
inflamed.
49. When the quantity of common fire in the body is small, the
quantity of the electrical fire (or the electrical stroke) should be
greater: if the quantity of common fire be great, less electrical
fire suffices to produce the effect.
50. Thus spirits must be heated before we can fire them by the
electrical spark.[46] If they are much heated, a small spark will do;
if not, the spark must be greater.
51. Till lately we could only fire warm vapours; but now we can burn
hard dry rosin. And when we can procure greater electrical sparks,
we may be able to fire not only unwarmed spirits, as lightning does,
but even wood, by giving sufficient agitation to the common fire
contained in it, as friction we know will do.
52. Sulphureous and inflammable vapours, arising from the earth,
are easily kindled by lightning. Besides what arise from the earth,
such vapours are sent out by stacks of moist hay, corn, or other
vegetables, which heat and reek. Wood, rotting in old trees or
buildings, does the same. Such are therefore easily and often fired.
53. Metals are often melted by lightning, though perhaps not from
heat in the lightning, nor altogether from agitated fire in the
metals.--For as whatever body can insinuate itself between the
particles of metal, and overcome the attraction by which they cohere
(as sundry menstrua can) will make the solid become a fluid, as
well as fire, yet without heating it: so the electrical fire, or
lightning, creating a violent repulsion between the particles of the
metal it passes through, the metal is fused.
54. If you would, by a violent fire, melt off the end of a nail,
which is half driven into a door, the heat given the whole nail,
before a part would melt, must burn the board it sticks in; and the
melted part would burn the floor it dropped on. But if a sword can
be melted in the scabbard, and money in a man's pocket by lightning,
without burning either, it must be a cold fusion[47].
55. Lightning rends some bodies. The electrical spark will strike a
hole through a quire of strong paper.
56. If the source of lightning, assigned in this paper, be the true
one, there should be little thunder heard at sea far from land. And
accordingly some old sea-captains, of whom enquiry has been made, do
affirm, that the fact agrees perfectly with the hypothesis; for that
in crossing the great ocean, they seldom meet with thunder till they
come into soundings; and that the islands far from the continent have
very little of it. And a curious observer, who lived thirteen years
at Bermudas, says, there was less thunder there in that whole time
than he has sometimes heard in a month at Carolina.