INTERPRETATION OF COMETIC PHENOMENA.
Now, curiously enough, we have in constant use in our laboratories a
little instrument called the electroscope, in which we have manifested
very clearly a repulsive force exceeding in energy the earth's
attracting power, and very greatly exceeding it. It is described in
"Electricity in the Service of Man" as follows: "If we rub a large
glass rod with a silk pad, we observe that it will attract light
bodies, then, after contact, repel them. During the process we may
notice a peculiar noise, and if the experiment be carried out in
the dark we may further notice sparks passing between the rod and
the rubber, and also that the rod becomes luminous. If we suspend
a pith-ball by means of a silk thread, on bringing the rubbed rod
near the pith-ball it will move towards the rod, touch it, and then
be repelled. If the glass rod be again brought near the pith-ball, it
will move away from the glass rod, and continue to be repelled until it
has been touched by some other body.... In order to ascertain whether
electricity is communicated by electrified bodies to non-electrified
bodies when brought into contact, let us suspend two pith-balls from
the same point of support by threads of uniform silk, and touch the
pith-balls with the rubbed glass rod. The balls fly from the rod and
also from one another. On bringing near them a third pith-ball or
any other light body, we find that, though they repel one another,
they are attracted by the light body, showing that they have become
electrified by contact with the rubbed glass rod. From this we
conclude that an unelectrified body may be electrified by contact
with an electrified body, and also that there is repulsion after
contact. There is mutual repulsion between two electrified bodies,
but there is attraction between a single electrified body and one
that is unelectrified." The mutual repulsion of these pith-balls
is the exact measure of the strength of electrification. Hung
side by side to the knob of a prime conductor of an electrical
machine, the mutual repulsion of the similar electrospheres of
these pith-balls drives them apart against the earth's gravity
and holds them extended, if the electrical tension be sufficient,
to their widest limit of divergence. It is, in effect, precisely
similar to the action of the solar and cometic electrospheres (see
illustration in a previous chapter, page 124), each being similarly
electrified and communicating with the other across a space which,
as before stated, is freely traversable by electric currents without
appreciable resistance. That such electrospheres are flaming with
heat does not interfere with such self-repellent action; in fact,
it intensifies it. In Professor Tyndall's "Lessons in Electricity"
we read, "Flames and glowing embers act like points; they also rapidly
discharge electricity. The electricity escaping from a point or flame
renders the air self-repulsive. The consequence is that when the hand
is placed over a point mounted on the prime conductor of a machine in
good action a cold blast is distinctly felt.... Wilson moved bodies
by its action, Faraday caused it to depress the surface of a liquid,
Hamilton employed the reaction of the electric wind to make pointed
wires rotate. The 'wind' was also found to promote evaporation."
Let us now apply these principles to the tails of comets. If
we conceive the sun and comet to be analogous to our pith-balls,
one enormously larger than the other, however, and hung by vaporous
conducting cords from the combined generating planetary electrospheres,
both sun and cometic nucleus surrounded each by a vaporous envelope,
and suspended so that they will hang from parallel cords, say a
dozen million miles apart, and with no currents of electricity as
yet in operation, we will find that the sun and comet will be simply
attracted towards each other by the force of gravity, so that their
suspending cords will converge. If the planetary electrical machines
now commence their rotations, and currents of electricity begin to pass
in quantity and intensity like those which pass between the earth and
the sun, both the solar and cometic pith-balls will become similarly
electrified, and their gaseous atmospheres, instead of drawing
towards each other, will become luminous and self-repulsive. The
atmosphere which surrounds the cometic pith-ball, by reason of
its great tenuity, will be driven backward with extreme velocity,
while the solar pith-ball electrosphere will be so little affected
that its repulsion will be imperceptible. All the gaseous matter,
however, of the smaller pith-ball will be forced off in a direction
opposite that of the larger one, and this repulsive energy will even
carry the pith-balls apart, causing the suspending cords to widely
diverge from each other, while the force of gravity of the earth
tends to bring them nearer together. If the gravity of the larger
pith-ball, however, was equal, relatively, to that of the sun, the
result would be that the solid pith-balls would be mutually attracted
by gravitation and only the electrified atmospheres, would be mutually
repelled. This experiment would present phenomena similar to those
we are now considering. (See illustration, page 211.)
In describing Newton's comet, with a tail ninety million miles long
projected backward both from the sun and the comet, when it disappeared
in the light of the sun, and exhibiting a similar tail, also ninety
million miles long, when, less than four days afterwards, it reappeared
from behind the sun, but with the tail now directed forward from the
comet, but in both cases extended radially outward from the sun, it
is obvious that this whole tail must have made a sweeping change of
direction of nearly one hundred and eighty degrees upon the nucleus
as its center. Professor Proctor says, "As Sir John Herschel remarks,
we cannot look on the tail of a comet as something whirled round
like a stick as the comet circles around its perihelion sweep. The
tail with which the comet reappeared must have been an entirely new
formation." It is true that a comet's tail cannot be conceived of as
being whirled round like a stick, but we can very readily conceive
of it as something like a flame composed of incandescent gases,
and it may very easily be blown round a stick; and this is precisely
what must happen in the case of a comet. Construct, for experiment,
a little apparatus consisting of a blow-pipe adapted to deliver a
current of air between two horizontal metal disks, say an eighth of
an inch apart, one perforated at the center to admit the nozzle of
the blow-pipe. By directing a constant current of air through the
latter, it will be deflected so as to blow radially outward in all
directions and in the same plane. Now take a stick with a flame on
the end of it, or a lighted candle, and with it approach this center
of repellent energy in the plane of the space between the disks and
along an ellipse representing the orbit of a comet. As the flame
approaches the improvised solar center it will be driven backward
from the wick of the candle almost along the line of its approach,
and as it passes around the center it will be constantly blown outward
in a radial direction until, when it recedes after perihelion, the
flame will be seen pointed almost directly ahead. At all times the
direction of the flame will lie along the radial lines prolonged
outward from the center through the wick of the candle, and it will
not be a new flame generated at every change of its direction, but
the same flame constantly forced outward by the repulsive force of
the central atmosphere in this case or the solar electrosphere in
the case of the sun. This experiment is an accurate and conclusive
exhibit of the phenomena of solar repulsion in its action upon the
tail of a comet. It is analogous in principle to the repulsion of
the pith-balls and the electric wind and (in application) to the
phenomena presented by comets in their movements to, around, and
from the sun. This repulsion is not operative in effect against the
wick of the candle,--that is to say, it is not the repulsion of the
nucleus which determines the direction of the tail, but the repulsion
by direct outblow of the sun, so to speak, upon the incandescent
gases of the tail itself. This fact clearly demonstrates that the
repulsion of like electrospheres is the cause of the phenomenon, and,
when once understood, the process is quite as simple as that of the
original formation of the tail itself, which no one disputes.
There is to be further considered the theoretical resistance of
space to the projection and deflection of such enormous volumes
of attenuated matter as appear in comets' tails. While it may not
be absolutely necessary to offer an explanation of this apparent
difficulty, in view of the fact that such projection and deflection
do actually occur, still, the well-known laws of the diffusion of
gases, in accordance with which any gaseous matter will traverse
any other gaseous matter with the same velocity as, and with no more
resistance than, in a vacuum, will show that this difficulty has been
much overrated, while for the twin difficulty, how to account for the
persistence of luminosity at such vast distances from its source, we
may quote from Professor Proctor, "Cometic Mysteries," who, in turn,
quotes as follows: "Comets travel in what must be regarded as to
all intents and purposes a vacuum. From Dr. Crookes' experiments on
very high vacua we may infer that there is very little loss of heat,
except by radiation." By "intents and purposes" we understand, of
course, as a cause of resistance, and certainly there is no reason to
believe that the attenuated vapors of space are sufficient in density
to cause any rapid diffusion of heat by convection, as contrasted
with that of radiation.
We have seen that comets of short period sometimes disappear, and
that their disappearance is frequently followed by the appearance
of trains of meteors. In other words, they have apparently lost
their cometic properties and become permanent adjuncts to our solar
system. A curious confirmation of this fact is to be found in the
character of the occluded gases which are contained in such meteorites
as sometimes fall upon the earth's surface. Of this Professor Proctor
says, "We have reason to believe that the nucleus of a comet consists
of an aggregation of stones similar to meteorites." Speaking of
the condition in which meteorites reach the earth, he says, "They
are known to contain as much as six times their own volume of gases
(taken at atmospheric pressure). In one of these meteorites recently
examined by Dr. Flight, the following percentages of various gases
were noted: Of carbonic oxide, 31.88; of carbonic acid gas, 0.12; of
hydrogen, 45.79; of olefiant gas, 4.55; and of nitrogen, 17.66." The
presence of olefiant gas at once suggests the hydrocarbons of the
cometic nucleus. The presence of this gas cannot be accounted for by
the passage of the meteorite through our atmosphere, nor can that of
hydrogen, and these are two characteristic gases, together with the
vapor of carbon, constantly found to exist in comets.
As before explained, the advent of a comet into our solar system
is that of a stranger, with electric polarity the opposite of
that of the planetary electrospheres and identical with that of
the sun. Under the combined influence of the solar gravity and
perturbation by the gravity of the planets these foreign bodies
tend to shorten their periods, and finally fall into the ordinary
array of the bodies which compose our own solar system. But when
this occurs they will, in turn, become contributors to, instead of
antagonists of, the energy of the sun; in other words, they must then
conform electrically to the condition of the family into which they
have married,--that is to say, the planets,--and a reversal of their
electrical polarity will take place. This reversal of polarity is no
novelty in the operation of electrical apparatus. In "Electricity in
the Service of Man" we read as follows of the Voss induction machine:
"This machine is exceedingly powerful in favorable weather, but has
an important defect in a tendency to self-reversal, which is apt to
occur at a stoppage. This defect can be produced in a Voss machine,
when desired, by holding a metal point to the positive brush K. The
two derived inductive circuits are beautifully manifested when this
machine is worked in the dark. A luminous stream is seen pouring
towards the collecting comb L on whichever side of the machine the comb
is positive." It will thus be seen that simple contact of a neutral
(or negatively opposite) body will reverse the electrical polarity
of this machine, or even the interruption of its motion will do so
at times. Possibly a similar reversal may be produced in a comet
by the contact in whole or in part of its nucleus with a planetary
electrosphere, since the action of gravity is entirely independent
of that of the attraction or repulsion of the electrospheres of both
planetary and cometic bodies. Such reversal of polarity in a comet
would at once extinguish its luminosity, and the generation of oxygen
would at once replace the prior generation of hydrogen, and herein
we may find explained the presence of carbonic oxide in large volume
and carbonic acid in small volume in the meteorite above referred to,
and of which gases Professor Proctor says, "It is quite certain these
gases were not taken up by the meteorolite during its flight through
the air." These aggregations of discrete meteoric bodies, loosely
adherent by mutual gravity alone, would be gradually torn apart by
planetary interference and dragged into streams of small bodies,
thenceforth traversing space in elliptical orbits around the sun,
just as do the planets and planetoids. Cyanogen, also, the deadly gas
so frequently found to exist in enormous quantities in the nuclei of
comets, would at once disappear, by double conversion into carbonic
acid, or oxide, and ammonia, or nitrogen, so that this danger, as
the result of a comet's possible approach to the earth's atmosphere,
may be dismissed from apprehension.
It will be seen that all the enormous difficulties in the phenomena
of comets find an explanation in the operation of the same universal
laws which we have endeavored to apply to the other sidereal bodies. In
conclusion, we may cite the following from Dr. Huggins: "Broadly, the
different applications of principles of electricity which have been
suggested group themselves about the common idea that great electrical
disturbances are set up by the sun's action in connection with the
vaporization of some of the matter of the nucleus, and that the tail
is probably matter carried away, possibly in connection with electric
discharges, under an electrical influence of repulsion exerted by the
sun. This view necessitates the supposition that the sun is strongly
electrified, either negatively or positively, and, further, that in
the processes taking place in the comet, either of vaporization or
of some other kind, the matter thrown out by the nucleus has become
strongly electrified in the same way as the sun,--that is, negatively
if the sun's electricity is negative, or positively if the sun's is
positive. The enormous disturbances which the spectroscope shows
to be always at work in the sun must be accompanied by electrical
changes of equal magnitude, but we know nothing as to how far these
are all, or the great majority of them, in one direction, so as
to cause the sun to maintain permanently a high electrical state,
whether positive or negative." The above speculations will have thus
become demonstrated facts (though not in the mode suggested by the
above writer) as soon as we clearly understand that, instead of the
sun's "enormous disturbances" producing "electrical changes of equal
magnitude," it is the electrical changes of equal magnitude which
themselves cause the sun's disturbances, and that the sun's negative
electrical polarity is permanently fixed by the opposite and positive
polarity of the planetary electrospheres, and that all these various
phenomena are but the normal expression of a single universal law,
and are all due to the constant interaction of planetary, solar,
and cometic electrospheres, in accordance with the well-established
principles of electrical science. If, however, we consider, as is
generally believed to be the case, the sun itself to be the sole
prime source of its visible energy, nothing but difficulty and vague
speculation can be looked for on every hand; but by relegating the
solar orb to its proper place, and taking as the starting-point the
true source of all energy,--to wit, the hidden forces embodied in the
vapors or gases of interstellar space,--the whole process and mode of
action will logically follow, and obscurity and difficulty together
disappear. This principle, properly understood, is a master-key which
will unlock every problem and interpret every enigma which the realms
of interstellar space can present.