THE SOURCE OF SOLAR ENERGY.
The remarkable resemblance between the mode of operation and effects of
these electrical induction machines and the vast rotating electrosphere
of the earth must be at once apparent. The operation is precisely
the same, and the results must, pari passu, be substantially
similar. We need not seek for precise parallelism of structure,
because these machines themselves, it has been shown, widely differ
in structure among themselves. But the almost infinitely more vast
terrestrial electrosphere, which cannot be less than ten thousand
miles in diameter, and perhaps much more (if we may form an opinion
from the relative magnitude of the field of action of the hydrogen
envelope which constitutes the solar electrosphere), rotating in the
attenuated vapors of space, among which vapors that of water plays a
most important part, and which vapors constantly impinge with various
disturbances of contact against the more and more attenuated layers of
the terrestrial atmosphere, and which gradually, from within outward,
less and less partakes of the earth's rotation until, finally, its
rotatory movement is lost in the vast ocean of space, establishes
the certainty that enormous quantities of electricity must there be
disengaged, precisely as in the machines which we have described,
and to learn the potential or active pressure of this electricity
we have only to consider the fact that we find a rise so rapid,
as we ascend through our atmosphere, that the potential increases
by from twenty to forty volts for each foot. That these currents
are transmitted to the sun without appreciable resistance we already
know, and that they are there transformed into light and heat we can,
from the previously cited experiments, see.
But it may be urged that the resistance of such attenuated vapors in
space, and the generation of electricity in such quantities, would
inevitably retard and finally destroy planetary motion. The sufficient
answer to this is found in the consideration that the same facts must
exist under any possible mode of organization of our solar system,
and that such interference, besides, must have absolutely prevented
its formation at all, if such were the case. All the matter of our
planetary system together is only one seven-hundred-and-fiftieth
that of the sun; if this were added to the sun's bulk it would but
slightly enlarge it. But all this solar and planetary matter together,
if distributed over the space occupied by our planetary system,--and,
by the nebular hypothesis of the organization of our solar system,
this is requisite,--and having an axial diameter one-half that
of its equatorial (see Proctor's "Familiar Essays on Scientific
Subjects,"--"Oxygen in the Sun"), would have had a density of only
about one four-hundred-thousandth that of hydrogen gas at atmospheric
pressure. This nebular mass must have had a diameter at least sixty
times that of the distance of the earth from the sun and a depth
of thirty times its distance. That this enormous mass of attenuated
matter should ever have been made to rotate as a whole by any force of
attraction, repulsion, or rotation, with a tenuity so great that, if
measured by an equal volume of hydrogen gas,--the lightest substance
known to us,--it would have furnished material for four hundred
thousand such systems as ours, presupposes a resistance so slight
that the planets themselves, when coagulated out of such a mass,
could never in any conceivable time exhibit retardation from such
a source; and we know to a certainty that such attenuated vapors do
exist in space, for electricity cannot be transmitted through a vacuum,
and it is transmitted with perfect freedom between the earth and the
sun. But it may be said that the laws were then different. If they
were different then, they are doubtless different now. If, on the
other hand, we assume that the bodies of which our solar system is
composed were simply aggregated into concrete masses from meteoric
dust, the difficulty is not lessened; for if the resistances to their
operation now are such as to perceptibly retard their motions, they
must have operated still more powerfully to originally prevent them;
while, if hurled forth by an almighty fiat, complete from the hand
of creative energy, the same force which impelled them forward must
have also established the laws under which they now move.
It is calculated that our earth must be losing time, by tidal
retardation, at the rate of one-half the moon's diameter in each twelve
hundred years (see Proctor, "Light Science for Leisure Hours,"--"Our
Chief Timepiece Losing Time"), and that "the length of a day is now
more by about one eighty-fourth part of a second than it was two
thousand years ago." Perhaps, however, we may discover that these
changes are themselves periodic and increase in cycles to a maximum,
and then diminish, as is the case with magnetic, planetary, and stellar
variations, and other similar changes, when sufficiently long observed;
for while such changes may very well accompany a theory under which
our system and all other systems are slowly running down to decay and
death, it is entirely incompatible with the primal forces under which
they must have been originally formed. In other words, if the tides
are dragging back our earth without compensation, this dragging back
can only come from the oceanic deposit of water on the earth from
the aqueous vapors of space which do not partake of the planetary
rotation and orbital movement of the earth. But if these can now
retard the earth's motion, they must have originally prevented it in
the beginning. This loss of time is, moreover, merely inferential from
mathematical computations, and its basis is found in the belief that
all the operations of nature are in a slow process of degradation,
and the calculated loss itself may be merely theoretical, and not true
in fact. Professor Proctor himself concedes the uncertainty of this
alleged retardation when he says in the same article, "At this rate
of change our day would merge into a lunar month in the course of
thirty-six thousand millions of years. But after a while the change
will take place more slowly, and some trillion or so of years will
elapse before the full change is effected."
While the processes of nature are generally believed to be running
down, everything is bent to that belief; but the forces of nature
must, nevertheless, be uniform and supreme, for it is by these forces
that the expected results are to be achieved. That changes occur
constantly is inevitable, but the source of these must be looked for
in the interaction of original forces, and not in the degradation
of systems. There is reason to believe, in fact, that the repulsion
of the terrestrial electrosphere by that of the moon may itself
be sufficient to counteract such retarding force of lunar gravity,
for the tides upon earth are not merely oceanic, but atmospheric,
and on the latter the electrical repulsion of the moon must act very
powerfully and with directly counteractive effect.
Let us now apply the preceding principles to the problem under
review. All planetary space is pervaded with attenuated vapors or
gases, among which aqueous vapor occupies a leading place. The planets
and all planetary bodies, having opposite electrical polarity from
the central and relatively fixed sun, by their orbital motions around
and constant subjection thereto act as enormous induction machines,
which generate electricity from the ocean of attenuated aqueous vapor,
each planet being surrounded by an enormous electrosphere, carried
with the planet in its axial and orbital movements, the successive
atmospheric envelopes gradually diminishing in rotational velocity
until merged into the outer ocean of space. As the planets advance in
their orbits they plunge into new and fresh fields, and, as the whole
solar system gradually moves onward through space, these fields are
never re-occupied. These electrospheres, by their rotation, generate
enormous quantities of electricity at an extremely high potential,--so
high that we can scarcely even conceive it,--and this electricity flows
in a constant current to the sun, where it disappears as electricity,
to reappear in the form of solar light and heat. These planetary
currents also flow towards such other negatively electrified bodies
as may exist in space--the comets and fixed stars, for example--in
proportion to their distance; for, since resistance is not appreciable
between ourselves and the sun, as is also the case with light, so, like
light, our electricity must pass outward as well as inward to take part
in the harmonious operations of the whole universe. But it should be
noted that the distribution of electric energy in the form of currents
is quite different from that of light or other radiant energy; for
while light is diffused from a center outward through space, electric
currents, on the contrary, are concentrated and directed along lines
of force to concrete centers of opposite polarity. As a consequence,
the intensity of light decreases according to the squares of the
distances traversed plus the resistance to the passage of the light
itself, while the electric current is only diminished by the resistance
of the medium through which it passes. As the light of the sun has a
velocity of one hundred and eighty-eight thousand miles per second,
and the electric current between the earth and the sun the same,
it will be seen that the resistance is practically alike for these
two forms of energy. Indeed, the striking resemblance between the
ethereal vibrations which constitute light and heat and exceedingly
rapid alternating currents of electricity through molecular media may
suggest that the transformation of one force into the other is some
sort of a "step-up" or "step-down" process, much higher in degree,
but of the same character as the well-known analogous electrical
transformations used in the arts. It should also be borne in mind
that, while the intensity of light diminishes according to the above
law, the quantity remains the same, less resistance, as the area
covered increases precisely in the same proportion as the intensity
diminishes,--that is, in the ratio of squares.
Around the earth and other planets gravity attracts the aqueous vapors
in increased density, the same as around the sun; but the electric
currents passing between the planets and the sun decompose this aqueous
vapor into its constituent gases, hydrogen and oxygen. The oxygen is
deposited within the positive electrospheres of the planetary bodies,
where it mingles with nitrogen to form our atmosphere and those of
the other planets. In this float the aqueous vapors condensed from
space, which are lighter than air. (See Tyndall, "The Forms of Water:"
"It also sends up a quantity of aqueous vapor which, being far lighter
than air, helps the latter to rise.") These aqueous vapors, condensed
into clouds and precipitated upon the earth, form our oceans and their
affluents. The hydrogen gas disengaged upon the sun's surface forms
a similar envelope, which is penetrated by the planetary electric
currents, and is thus highly heated and rendered incandescent; the
glowing hydrogen transmits its heat to the sun's mass within, which
is thus raised to, and permanently maintained in, a liquid or densely
gaseous state, its metallic constituents being volatilized in part,
and these metallic vapors mingle with the lower strata of hydrogen
to form the sun's photosphere, while, above, the glowing hydrogen
grows more pure, and finally, at a distance of hundreds of thousands
of miles, is merged into the corona, which is composed, in part at
least, of cosmical dust rotating around and repelled by the sun,
and which shines partly by reflected light, partly by that of the
relatively cooler hydrogen, and partly, perhaps, by electrification
of its constituents by the powerful currents passing through it. Each
of the planetary bodies, large or small, takes its proportionate part
in the generation and transmission of electricity, according to its
volume, mass, and motion. As an adjunct to this electrical sequence
we have learned that any interruption of such currents between the
generator and the receiver will cause the generating apparatus to glow
with diffused electrical light, as is the case with the Wimshurst
machine already described. When such connection is removed, it is
said, "the whole apparatus bristles with electricity, and if viewed
in the dark presents a most beautiful appearance, being literally
bathed with luminous brush discharges." Such a phenomenon recalls at
once the aurora borealis; and when we find this as a sequence of the
electrical storm of the first of September, 1859, before described
("at night great auroras were seen in both hemispheres"), and connect
with this the persistence of electricity upon insulated surfaces (see
"Electricity in the Service of Man," page 53: "Glass being a bad
conductor, the electricity does not spread all over the plate, but
remains where it is produced"), we shall inevitably conclude that there
was some partial interruption in the current flowing from the earth
to the sun at that moment; and if we recall that at that very instant
"suddenly a bright light was seen by each observer to break out on the
sun's surface and to travel across a part of the solar disk," we shall
learn that the processes connected with the production of such a bright
light will interrupt in part the terrestrial current. We can readily
understand that if this bright light exceeded in electrical intensity
that due to the earth's current, it might temporarily reverse the
polarity of the afferent current or retard its flow, like the so-called
"backwater" of a mill. It would be like attempting to discharge steam
at sixty pounds' pressure into a vessel filled with other steam at
sixty-one pounds. Whence, then, came this bright light? Perhaps from
the conjoint action of some other planet, perhaps from sudden chemical
disassociation beneath the surface, perhaps by the abnormal piling up
of depths of transparent glowing hydrogen or other local disturbance.
And this leads to the consideration of the uniformity of solar
action. The planetary electrospheres will be constant in their
operation if the constitution of surrounding space remains uniform;
but we shall find reason to believe that there are currents in
the ocean of space, as there are currents in our own seas, and
electrical generation will necessarily vary when such currents are
encountered. The sun itself in such case, however, will become an
automatic regulator, for his density being but one-fourth that of the
earth, and the spectroscope having shown his chemical composition
to a large extent, we know that his mass must be either liquid or
vaporous, and perhaps in part both. Such masses readily respond to
variations of temperature, expanding as it rises and contracting as
it falls. Hence, if a portion of space were reached where the action
of the planetary electrospheres was increased by relative increase of
temperature in some interstellar "Gulf Stream," the sun's volume would
expand and compensation be at once established, while, conversely,
with diminution of such planetary action, the solar volume would
contract and an increased supply from his reserve store be given out
thereby. In this way the condensation relied upon to give us heat for
seven or seventeen million years becomes a compensating mechanism,
self-operative through the most distant cycles of time. We shall
also find in such electric currents an explanation of sun-spots. It
is not meant that a full knowledge can be obtained of their minute
constitution, nor is it necessary; but the equatorial belt of six
degrees, nearly free from sun-spots, we can readily understand to be
caused--since sun-spots are depressions in the photosphere down to
the deeper and denser cloud strata beneath--by the equatorial piling
up of the sun's atmosphere by its rotation. Any point on the sun's
equator travels at four times the rotational velocity of one on the
earth's equator, but the sun's attraction of gravity is twenty-seven
and one-tenth times that of the earth, so that the piling up of an
atmosphere of hydrogen would be considerable, and such depressions
would not ordinarily exist there. Similarly, near the sun's poles we
should find a gradual darkening, as is the case; but from five degrees
to thirty degrees latitude, the sun, in its rotation, by reason of
the inclination of its axis, passes at every point directly beneath
the planets, or within their area of control, and here we find the
solar spots in their greatest number, size, and intensity. These
sun-spots cross the face of the sun in about fifteen days, and vary
in development from year to year, having a cycle of 11.11 years from
maximum to maximum. They also have a long cycle of about fifty-six
years. (See article "The Sun," in Appleton's Cyclopædia.) "Wolf, in
1859, presented a formula by which the frequency of spots is connected
with the motions of the four bodies, Venus, the earth, Jupiter, and
Saturn. Professor Loomis, of Yale College, has since advocated a theory
(suggested by the present writer [Proctor] in 1865, in 'Saturn and
his System,' page 168, note) that the long cycle of fifty-six years
is related to the successive conjunctions of Saturn and Jupiter. But
the association is as yet very far from being demonstrated, to say the
least." Should such fact be established, an explanation for it will
be found in the direct impact of the condensed electric currents from
several planets approaching conjunction, and raising a portion of the
sun's atmosphere suddenly to a higher temperature and volatilizing an
abnormal proportion of the semi-vaporous metallic core beneath. This
would form an upburst piling the intensely heated faculæ up on the
sides and revealing the relatively darker masses of cloud beneath, the
cooler supernatant hydrogen pouring in from the upper layers to fill
the returning void. This is precisely what is seen in such spots and
their surrounding disturbances. In the article "The Sun," above quoted,
we read, "Mr. Huggins has found that several of the absorption bands
belonging to the solar spectrum are wider in the spectrum of a spot,
a circumstance indicative of increased absorption so far as the vapors
corresponding to such lines are concerned.... Near the great spots or
groups of spots there are often seen streaks more luminous than the
neighboring surface, called faculæ. They are oftenest seen towards the
borders of the disk." This writer also describes "luminous bridges
across spots which sink into the vortex and are replaced by others
of the numberless cloud-like forms from one hundred to one thousand
miles in diameter, the brilliancy of which so greatly exceeds that of
the intervening spaces that they must be recognized as the principal
radiators of the solar light and heat." The apparent retardation of
the spots most distant from the sun's equator may also be partially,
at least, explained by planetary currents of electricity, as the
equatorial atmosphere is deeper and more likely to carry forward
such vortices when formed, while the planets act more directly on
the sun's mass beneath their direct influence.
Let us consider this retardation of sun-spots somewhat more in
detail. Take, for example, the case of a large planet at such orbital
position that its direct line of electrical impact will penetrate
the photosphere at (say) seven degrees north solar latitude, which
is about fifty-two thousand miles from his equator. During its annual
revolution this planet will traverse, with its line of energy, every
point of the sun's surface down to seven degrees south latitude and
back again to its initial point, thus tracing a close spiral around
the sun for fourteen degrees, or about one hundred and four thousand
miles in width. The centrifugal force of the solar rotation piles
up the photosphere and the chromosphere around the sun's equator,
precisely as our atmosphere is piled up around our own equator. If
the planet be a large one (for distance has but little to do with
these electrical currents at planetary distances, in which they
differ entirely from light, heat, and gravity), or if there be two
planets nearly in conjunction, the body of the chromosphere and
the surface of the photosphere will gradually become highly heated,
for currents of electricity, of themselves, do not directly heat the
solar core any more than a like current heats the under carbon of an
arc lamp, the high temperature in both cases being altogether due
to the incandescent heat of the interposed arc or envelope. Faculæ
of intense brightness will then appear upon the photosphere, and
these will be driven forward and also outward in the direction of
the higher latitudes, producing an oblique forward movement from
difference of rotational speed at different portions of the sun's
surface. Similar phenomena are constantly observed on the surface
of the earth in the generation and behavior of cyclones and other
atmospheric disturbances. They may be compared to the wake of a vessel
anchored in a strong tide-way. These faculæ will slowly raise the
temperature of the surface of the sun's core beneath to the point
of eruptive volatilization, and particularly so if the planet is
receding from, instead of advancing towards, the solar equator. At
some point in advance of the line of planetary energy an eruption of
volatilized metals will suddenly occur, first thrusting up a vast
area of the photosphere and then bursting it asunder, which will
drive these ruptured masses with enormous speed forward and obliquely
outward from the equator. Such faculæ (see Proctor's "Light Science")
sometimes reach a velocity of seven thousand miles per minute, while
the sun's rotational movement at the equator is less than seventy
miles per minute. This sudden eruption will be almost immediately
succeeded by great expansion and consequent fall of temperature, so
that within a few hours the heavy volatile metals begin to condense
and rapidly recede into their crater, and the faculæ in front and at
the sides will now stream inward to occupy this vacuum with constantly
accelerated velocity, pouring over the edges like the rush of waters
at the Falls of Niagara. As they sweep downward over the inner rim of
the funnel, these streams of faculæ will glow with increased whiteness,
and appear to be sharply cut off at their inner ends; but this is only
apparently so, and is due to the position of the observer, who looks
almost directly downward upon these descending streams. It is for
the same reason that the faculæ appear more brilliant when near the
borders of the solar disk (see page 109). Any good view of a sun-spot
when analyzed will show the streams of faculæ thus pouring inward,
and they are among the most peculiar and conspicuous phenomena
to be observed. The drawings of Professor Langley, reproduced in
the Popular Science Monthly for September, 1874, and July, 1885,
are particularly striking in their illustration of these effects,
though their significance and interpretation were not then at hand.
But while these heavy metallic vapors so rapidly condense and subside
in the forward or initial portion of the sun-spot under observation,
new depths of intensely-heated faculæ are generated behind, and these
operate with renewed energy upon the fresh surface of the solar core
in rear of the original seat of eruption; so that each sun-spot,
while in an active state, will exhibit two entirely distinct aspects,
the forward portion of the crater in a state of rapid condensation
and subsidence of the recently erupted metallic vapors, and with
inflowing streams of incandescent hydrogen from the front and sides,
and the rear portion of the crater up to its rearward wall, and even
streaming forth from beneath it, in a state of violent eruption. The
large volcanic craters of the Hawaiian Islands exhibit similar
partial eruptions and subsidences progressing simultaneously in the
same depths. The sudden formation of the great incandescent loops and
plumes to which Professor Langley calls especial attention, and which
have hitherto been so perplexing, can now be readily understood and
explained. If one of these inflowing streams be carried partially
down into and across the crater, and then caught, in its advance,
by the uprush in the central or rear portions of the cavity, it will
be at once swept upward alongside the ascending eruption, and either
scattered at its forward extremity into sprays and plumes, or else
thrown forward bodily in the form of a more or less complete loop. In
a sun-spot fifty thousand miles in diameter, such a loop, having a
long diameter of twenty thousand miles, if we give a speed to the
faculæ of seven thousand miles per minute, would be formed in about
seven minutes, during which the sun-spot would itself have advanced
less than five hundred miles across the face of the sun. The luminous
bridges which form so suddenly across portions of the crater may be
explained in a similar manner: they are streams of faculæ floated on
the nearly balanced uprush of metallic vapors from beneath.
It will thus be seen that a sun-spot is not merely a fixed eruption,
like a volcano, but rather a continuous series of eruptions, like
a line of activity following, for example, the great terrestrial
volcanic curve which extends up the western coast of America, across
the Pacific Ocean and Asia, and into Central and Southern Europe,
for during its progression its scene of action is constantly being
shifted to the rear; it is like a furrow cut by a plough, in which
the upturned sod is constantly falling in at one end of the furrow
while the plough is cutting a new furrow at the other, except that
in this case the plough is relatively fixed overhead, and the field
itself passes along beneath it. Consequently, the center of activity
of a sun-spot is only in its rear portions, generally considered, and
the whole sun-spot is gradually retreating, by successive filling up in
front and opening out behind, farther and farther to the rear,--that is
to say, to the east,--so that retardation relatively to the rotational
advance of the photosphere necessarily ensues.
But when the sun-spot is developed upon or near the equatorial
line this retardation is not so considerable, for the deeper layers
of the photosphere in those regions are slower to act and require
greater energy to affect them, so that all except deep and violent
eruptions fail to show themselves at the surface at all, and the
heated faculæ are carried directly forward along the surface of the
equatorial swell, so that the center of activity is driven forward
more rapidly than in the higher latitudes, and the rate of progression
is more nearly coincident with that of the photosphere. But if these
facts are correctly stated and explained, we may have to revise our
calculations of the sun's rotational period, for retardation to some
extent must occur in all cases, if in any.
A sun-spot, we thus perceive, is an elongated wave or ridge of eruption
along the rotational direction of the sun's body. Why, then, it may
be asked, is not this line of eruption continuous entirely around the
sun? For the same reason, it may be answered, that our own cyclones
are not continuous, though caused substantially in the same manner,
and that volcanic eruptions only occur at long intervals, though
the forces at work are continuous. Lowering of temperature follows
swiftly after eruption, and as the deeper structures of the solar
nucleus become gradually affected, instead of volatilization of the
outer layers of the surface, we will have diffused gaseous expansion
of large portions, and finally of the entire solar mass, which cannot
as a whole be volatilized by any conceivable planetary energy. We see
these operations exemplified in heating a bar of copper in a Bunsen
flame; the latter first turns green from surface volatilization of
the copper, but as the heat is communicated to the deeper structures
the green flame disappears, and the whole additional heat goes to
raise the temperature of the mass.
These processes in the sun are thus seen to be self-compensatory in
their nature. They are the means provided to distribute the restricted
areas of abnormally heated photosphere over the solar surface, and
finally to cause the absorption of the whole excess of heat in the
sun's central mass. The balance is so evenly maintained, however, that,
were all the planets equally distributed with reference to the sun's
surface, such sun-spots would be the exception and not the rule, and
their distribution would be equal and constant; but, as the planets
continually change their positions with reference to the sun and to
each other, only by some such provision of nature could the internal
structure of the sun be maintained without serious derangement, or,
indeed, final disruption. So nature distributes her stores of heat
upon the earth. These beautiful self-compensations we shall find
suddenly appearing, as we advance, in all parts of the field of
astronomical research.
It may seem like temerity to advance statements so positive and
specific as to the cause, constitution, and progression of sun-spots,
in the absence of any considerable accumulation of observations
to sustain them, but the few examples which we have noted are in
accordance with these views, and when attention is once called to the
basic principles on which they depend, observations will doubtless be
made in abundance to prove or disprove what has been here stated. The
mere fact of a differential rate of advance among sun-spots, as they
pass across the solar face, of itself demonstrates that the active
causes of these phenomena must be extra-solar, and if so, their only
possible dynamic source must be looked for in the planets, and the
remaining conclusions will of necessity follow as a corollary. We may
even, by merely examining an accurate drawing of a sun-spot, determine
its position and direction upon the solar sphere from which it was
delineated by its lines of active eruption and influx of faculæ,
and also whether it be a new spot or one which has passed entirely
beyond its active stage and is about to finally disappear.
As for the faculæ which striate the photosphere, the mottlings and
so-called "willow-leaves," any one who will quietly gaze downward
upon the turbid surface of the Mississippi or other similar river,
in mid-channel, will see plenty of such faculæ: the river is full of
them. The heavier, intermingled clay, slowly subsiding, is caught up in
the turmoil beneath the surface and swept upward in elongated ovals and
eddies, the larger swells nearly colorless, and others of all shades
of ochre and yellow, and the whole as richly mottled, sometimes, as
the variegated pattern of a Persian carpet. If we substitute for the
subsiding clay the rapidly sinking heavy metallic vapors, and enlarge
the scale from the dimensions of the river to those of the sun, we
will have the mottled solar surface with its kaleidoscopic changes,
the so-called "willow-leaves," and the faculæ in all their glory. A
careful study of the sun will show most clearly that only in some
such explanation as the present view affords can a rational basis
for its varied phenomena be found.
If the sun's equator were coincident with the plane of the planetary
orbits, it is obvious that all the planetary energies would be
directed, whatever the position of the planets around the sun,
immediately upon this equatorial great circle, and that, at each
revolution upon his axis, corresponding nearly to our calendar month,
the same part of his sphere would be exposed to these direct currents,
so that the intensity would be, in its aggregate, nearly a constant
quantity. But, by reason of the sun's axial inclination of seven
degrees to the plane of the planetary orbits, a far more complex and
important condition of affairs ensues. It will be seen at once that
the plane of the planetary orbits intersects the sun's equator at
opposite sides, and that, from a minimum of nothing, this line reaches
a maximum, twice in each circumference, of seven degrees, one north
and the other south of the equator, and that this arc of fourteen
degrees, thus traversed by every planet in its orbital rotation
around the sun, measures more than one hundred thousand miles from
north to south upon the solar surface, nearly one-half the distance
which separates the earth from the moon. If all the planets were in
conjunction or nearly so, on one side of the sun, for example, and in
the vertical plane of the sun's axis, they would continue to deliver
their electrical currents with their greatest intensity upon a single
point of his surface fifty-two thousand miles north of his equator,
while the opposite point, one hundred and four thousand miles distant,
would be unaffected by any direct currents at all. Conversely, if
in conjunction on the opposite side of the sun, they would continue
to deliver these currents upon a corresponding point fifty-two
thousand miles south of the equator; but if in conjunction in the
vertical plane transverse to the sun's axial inclination, these
currents on either side of the sun would be delivered directly upon
the solar equator. The importance of this will be understood when
it is considered that for many of our years such planets as Jupiter
and Saturn must continue to direct their currents upon a very slowly
changing point of the sun's surface, by reason of their vast annual
rotational period, while with the earth and the interior planets these
various points are struck with ever-increasing rapidity as the year
decreases in length with the different planets, the earth, Venus,
and Mercury. There is a solar equinoctial, so to speak, just as there
is a terrestrial equinoctial in which the sun crosses the line twice
each year, and the meteorological disturbances faintly shown on the
earth at such times are vastly increased on the sun, and rendered
far more complex by the interaction of many planets upon the sun,
instead of a single sun upon each planet. While our equinoctial has
to do with gravity and light and heat, and probably magnetism, the
solar equinoctial deals with the vast electrical streams which feed
its fires and set it boiling with furious energy, first at one point,
then at another, until the increment has been absorbed and adjusted,
and thus equalized throughout his mass. What a new interest this must
arouse in our study of sun-spots, faculæ, prominences, sun-storms,
and the vast panorama of solar action hung up before our astonished
eyes! A new world here awaits its Columbus.
But not only the planets thus gather, so to speak, electricity for
the sun's support from space; the moon also must do its part, as it
rotates in the same manner, subject to the sun, and has its own motion
through space. But an examination of the moon shows no atmosphere
and no aqueous matter visible to us, and also the singular fact
that it constantly presents one side only to the earth. R. Kalley
Miller, in his "Romance of Astronomy," article "The Moon," says,
"After an elaborate analysis, Professor Hausen, of Gotha, found that
it could be accounted for only by supposing that the side of the moon
nearest us was lighter than the other, and hence that its center of
gravity was not at its center of figure, but considerably nearer
the side of it which is always turned away from us. He calculates
the distance between these centers to be nearly thirty-five miles,
evidently a most important eccentricity, when we remember that the
radius of the moon is little over a thousand miles. It must have been
produced by some great internal convulsion after the moon assumed its
solid state; but the forces required to produce this disruption are
less than might at first sight appear necessary, owing to the fact
that the force of gravitation and the weight of matter are six times
less at the moon than with us." Those who are fond of the so-called
"Argument of Design" will be gratified to learn that, if the moon
had a rotation upon its own axis similar to that of the earth,
all life--past, present or future--would have been impossible on
that satellite or planet; and that, on the contrary,--provided she
always turns the same side of her surface to the earth,--it is quite
possible that air, water, and life may exist, or may have existed,
on the opposite side of the moon, but not otherwise. In fact, air and
water must now exist on the opposite side; and, since her whole supply
will thus be condensed upon half her surface or less, even with her
small force of gravity, it may be quite sufficient in quantity and
density for the support of animal, vegetable, or even human life. By
reason of this difference in the lunar center of gravity, the side
presented to the earth in physical position is similar to the summit
of a mountain upon the earth's surface two hundred miles high, and
surely we would not expect to find much air or water or life at that
altitude. But the opposite side would resemble a champagne country
at the foot of this enormous mountain, and might be well fitted for
human existence. Now, we know that similar electricities repel each
other, and air or gases charged with similar electricities are equally
self-repellent. Professor Tyndall, in his "Lessons in Electricity,"
says, "The electricity escaping from a point or flame into the air
renders the air self-repulsive. The consequence is, that when the
hand is placed over a point mounted on the prime conductor of a good
machine, a cold blast is distinctly felt.... The blast is called the
'electric wind.' 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."
While electrical repulsion is doubtless analogous to, and correlative
with, the attraction of gravitation, this force, and even gravity
itself, has been sometimes interpreted as derived from the mutually
interacting molecules of space itself. We may even learn somewhat
of how such repulsions of similar and attractions of opposite
electrospheres might occur. We constantly speak of positive
and negative electricity as though these were different fluids,
but such expressions are employed only in the same manner as the
analogous terms, heat and cold. We know, of course, that cold is the
relative absence of heat, the dividing line being not a fixed, but a
constantly changing one, so that one body is cold to another by reason
of relative, and not absolute, deprivation of heat. It is well known,
however, that cold, which is purely a negative state, manifests the
same apparent radiant energy as heat. A vessel near an iceberg is
exposed to a wave of cold, precisely as of heat from a heated body at
the same distance. This, of course, is due to abstraction and not to
increment. All space being occupied by attenuated matter in a state
of unstable electrical equilibrium, as we say, which simply means
a condition ready to be raised or lowered in tension by absorption
from or into outside media, all concrete bodies floating in that
space must have an electrical potential either equal to, or higher,
or else lower than that of their surrounding space. A solitary body in
space, if we can conceive of such, in either a higher or lower state
of electrical tension, would be drawn upon from all sides to equalize
the distribution and restore the general average. But if two bodies
occupy the same field, and are widely different from each other in
electrical potential, one higher and the other lower than that of
space, this distribution will be towards each other, and must be
manifested by mutual attraction. But if, on the contrary, these two
bodies are both equally higher or lower than the spatial average,
they have nothing to give to each other, but have this difference
to give to or receive only from outer space, and hence they will be
drawn apart or, as we say, mutually repelled. The case is similar to
what we see in the case of bodies of water at various levels. Suppose
there be a lake of a fixed level, and communicating with it and with
each other, by open channels, two ponds of water occupying an island
in the middle of the lake. If one of these ponds be higher in level
and the other lower than the lake, their waters will rapidly converge,
the higher flowing into the lower; but if both are at the same level,
and higher than the lake, they will flow apart into the lake. Or, if
both are at the same level, and lower than the lake, the water of the
latter will equally flow from outside into both ponds, and their waters
will still be held separate from each other. The analogies of these
various levels may be pursued to any desired extent, as electrical
tensions find their most exact analogies in the pressures of bodies
of water at different levels and of different quantities, and these
analogies are those most constantly used in the interpretation of
such electrical phenomena.
The great electrical activity of the electrospheres of the earth and
moon, while they discharge their tremendous currents directly into
the sun, at the same time must cause their similarly electrified
atmospheres to mutually repel each other, while gravity continues
to operate to maintain the earth and moon at their fixed distances
from each other, and to retain their gaseous envelopes around their
own bodies. The result must be that these similarly electrified
atmospheres repel each other with a force proportioned to their masses
of atmosphere and the intensity of the electricities of each. The
moon's axial rotation being completed but once in twenty-eight days,
and that of the earth once in each day, and the moon's mass and volume
being so much less than those of the earth, whatever of electrified air
or moisture she may have (and she must have both, proportionate to her
attributes) would have been driven as by a cyclone to the opposite side
of the moon and there retained. Now, with an atmosphere and water only
on one side of the moon, and that the side opposite the earth, it is
obvious that a rotation on her axis at all resembling that of the earth
would carry every part of her surface, at each complete rotation, from
a region of air and moisture into one deprived of both, and in such
a condition she would of necessity be deprived of both life and its
possibility; hence, as the laws of nature compel the lunar atmosphere
and moisture to reside permanently on the side always opposite the
earth, a co-ordinate arrest of the moon's axial motion with reference
to the earth could alone compensate for such a state of things,
and, curiously enough, we find as a solitary exception, compared
with the planets, that such is the case. The moon unquestionably has
both atmosphere and water on its opposite side. In his recent work,
"In the High Heavens," Professor Ball reviews the physical conditions
of the other planets as possible abodes of life. He pronounces against
the moon because night and day would each be a fortnight in length;
but this is surely no objection, for even in Norway and Greenland such
nights and days are not uncommon at different seasons, and thousands
of human beings, even as at present constituted on earth, spend their
lives there in content and happiness. That the moon also would be
terribly scorched by the long day and frozen by the long night does
not necessarily follow, for the atmosphere of Mars, that author says,
"to a large extent mitigates the fierceness with which the sun's rays
would beat down on the globe if it were devoid of such protection." As
the moon's opposite face must have a double quota both of atmosphere
and clouds, the difficulty will be correspondingly less than on Mars;
and as for the "lightness" of bodies on the moon, they would probably
get along quite as well as mosquitoes and like "birds of prey" in the
marshes along our coasts. The author refers constantly to our bodies;
for example, "Could we live on a planet like Neptune?" No, we could
not; we would be dead before we got there. Nor could we live in the
bark of a tree, or at the bottom of the ocean, or in a globule of
serum; but living beings are found there nevertheless. The principle
is that wherever life is possible there we may expect to find life;
and surely life is, or has been, or will be possible, not only on
the moon, so far as our knowledge of physical conditions can go, but
also on some of the other planets. Of course each planet has its life
stage, but this applies not only to the earth, but to all the other
planets as well, and not only to the planets of our own system, but
to those of all other solar systems. Each has had, or will have, its
stage in which life is possible, and these planets may be like human
habitations, in which whole races at times migrate from one home to
another. There is no conceivable reason why this may not be the general
law of creation, and every analogy leads us to believe that it is so.
It has been recently announced that, from telescopic observations,
the atmosphere of Mars must be at least as attenuated as that among
the highest mountainous regions of the earth, if this planet has any
atmosphere at all. That it must be far less dense than that of the
earth at sea-level is obvious, for the mass and volume of Mars are
very much less than those of our own planet; but that Mars is devoid
of a gaseous envelope or atmosphere is contrary to what we know of all
sidereal physics. The sun, the fixed stars, the comets, the nebulæ,
and even the meteorolithic fragments which fall upon the earth, all
show the same elementary chemical constitution as the earth itself,
and we cannot believe that Mars alone is differently constituted from
every other body we have been able to examine. We have direct evidence,
on this planet, of polar snows and their melting away under the sun's
heat; we see the apparent areas of sea and land; it has its moons as
the earth has hers, and exhibits all the characteristic phenomena of
the earth and other planets. All sidereal bodies that we know of,
except, perhaps, our moon, which exception we have fully accounted
for, are found to be surrounded by gaseous envelopes or atmospheres
of some sort. The sun, the fixed stars, the nuclei of comets, the
condensing nebulæ, the planets Jupiter and the earth, which are
those under our most direct observation, and even the meteorites,
when examined, reveal the presence of many times their own volumes of
independent atmospheric gases; and whatever may be the theory of the
origin or development of Mars, it must have been subjected to the same
influences, the same environment, and the same processes of creation as
those of our solar system generally; and that this body alone should
possess no gaseous envelope--for the denial of atmosphere denies,
at the same time, the presence of any or all surrounding gases--is
quite incredible. Only the most positive, direct, and long-continued
proofs of such fact could be accepted, and even then the history of all
scientific progress shows that what are believed to be facts themselves
fluctuate like fancies till, by their accumulated force, they solidify
into universally accepted demonstration. The fact, moreover, that
the atmospheres of the smaller planets are more attenuated than our
own and those of the larger ones denser has no bearing, in itself,
on the probability of the existence of life on these other planets,
for in our own atmosphere oxygen, which is the efficient element,
is diluted with four times its quantity of inert nitrogen. These
proportions doubtless vary largely in other atmospheres, so that
the oxygen may be much richer in some and far poorer, relatively,
in others. The mere fact that the presence of nitrogen, probably, and
aqueous vapor, certainly, depends on the gravity of the mass of each
planet, while the oxygen is due to electrolytic decomposition induced
by the combined volume, mass, and rotation, and other causes,--such
as the axial inclination of such planets, for example,--renders
these variations in the constitution of planetary atmospheres a
certainty. As Mars has a diameter much more than one-half that of
the earth, and a diurnal rotational period nearly the same, while his
mass, which controls the action of gravity, is only about one-ninth
that of the earth (see Appleton's Cyclopædia), it is obvious that his
oxygen-gathering power, compared with that for accumulating nitrogen
and aqueous vapor, is much higher than that of the earth, and we should
expect to find there an attenuated atmosphere very rich in oxygen,
and with a relatively smaller proportion of aqueous vapor, or even
water, on his surface. Such seem to be the facts as far as observed.
In operating an electric machine the strength of the current is
directly proportionate to the speed of rotation,--that is to say,
to the velocity of the generating surface; for example, of the
Wimshurst induction machine it is stated (page 63, "Electricity
in the Service of Man"), "These four-and-one-half inch discharges
take place in regular succession at every two and a half turns of
the handle." It is also a well-established law of electrolysis that
"The amount of decomposition effected by the current is in proportion
to the current strength." Professor Ferguson ("Electricity," page
225) says of the voltameter, an instrument devised by Faraday,
and used for testing the strength of currents by the proportionate
decomposition of acidulated water, "Mixed gases rise into the tube,
and the quantity of gas given off in a given time measures the
strength of the current." Roughly estimating the diameter of Mars at
five-eighths, the surface velocity at three-fifths, and the mass at
one-ninth those of the earth, this planet should have an atmosphere
containing about sixty per cent. of oxygen and forty of nitrogen, with
a barometric pressure at sea-level of about six and one-half inches of
mercury. This would be an excellent atmosphere,--about equal in its
quota of oxygen for each respiration to that of the higher areas of
Persia, a great country for roses. The aqueous vapors lying low and
near the surface would serve as a vaporous screen to concentrate and
retain the sun's heat and retard radiation from that planet. Nothing
in particular seems to be the matter with Mars.
On the contrary, the mass of Jupiter is so great, and his attraction
of gravity so powerful, that it is only by his exceedingly rapid
diurnal rotation (once in less than ten hours) that it is possible
for him to accumulate any effective percentage of oxygen at all. But
there is certainly plenty of water there.
We may approximately compute, in general terms, the proportion
of oxygen in the atmospheres of the other planets in the same
way. Neptune, it is true, is so far distant from the sun that the
solar orb only "appears about the same magnitude as Venus when at
its greatest brilliancy, as viewed from the earth," but we must not
forget that "the intensity of the sun's light would be more than ten
thousand times greater than that of Venus" (Professor Dunkin, in "The
Midnight Sky"). Unless the moon gathers a portion of the earth's oxygen
(the planetary satellites, like Saturn's rings, thus constituting
in their rotations a constituent part of the planets themselves),
the percentage of this gas in her atmosphere must be exceedingly
small, for her axial rotation has a period of a whole lunar month,
being the same as that of her revolution around the earth as a center.
The absence of apparent atmosphere and moisture from the visible lunar
surface has already been mentioned and explained. The means by which
this fact has been approximately determined are described by Professor
Dunkin, in "The Midnight Sky," as follows: "Among the many proofs of
the non-existence of a lunar atmosphere, it may be mentioned that
no water can be seen; at least there is not a sufficient quantity
in any one spot so as to be visible from the earth. Again, there are
no clouds; for if there were, we should immediately discover them by
the variable light and shade which they would produce. But one great
proof of the absence of any large amount of vapor being suspended over
the lunar surface is the sudden extinction of a star when occulted by
the moon. The author has been a constant observer of these phenomena,
and, though his experience is of long standing, he has never observed
an occultation of a star or planet, especially at the unilluminated
edge of a young moon, without having his conviction confirmed that
there is no appreciable lunar atmosphere.... Professor Challis has
subjected the results of a large number of these observations to a
severe mathematical test, but he has not been able to discover the
slightest trace of any effect produced by a lunar atmosphere."
In Appleton's Cyclopædia, article "The Moon," it is stated that
"Schröter (about 1800) claimed to have discovered indications of
vegetation on the surface of the moon. These consist of certain traces
of a greenish tint which appear and reappear periodically; much as
the white spots covering the polar regions of Mars.... As we are able,
under the most favorable conditions, to use upon the moon telescopic
powers which have the effect of bringing the satellite to within one
hundred and fifty to one hundred and twenty miles of us, we should
doubtless notice any such marked changes on her surface as the passage
of the seasons produces, for example, on our own globe." Very recently
(August 12, 1894), it has been stated, Professor Gathmann has observed
a peculiar green spot about forty by seventy miles in area near the
crater of Tycho Brahe, "on the northwestern edge of the satellite's
upper limb," which had disappeared twenty-two hours afterwards.
We understand, of course, that the moon's librations, by the variation
of position of the lunar body, enable us to see, at times, around
the edge of this satellite somewhat, so that, instead of observing
only one-half, we can in this way see nearly six-tenths of her
surface, but not at the same time, of course. When the moon is dark
it occupies a position between the earth and the sun, and only its
opposite face is illuminated. In this position the attraction of
solar gravity and the attraction of the electrically opposite solar
electrosphere both accumulate their forces upon the moon's atmosphere
in the same line as the repulsion of the earth's similar electricity,
so that the lunar moisture and atmosphere are, at this part of her
subordinate orbit, most powerfully forced away from the direction
of the earth. As the moon now proceeds towards her first quarter,
the terrestrial repulsion drives her atmosphere radially outward,
while solar gravity and electrical attraction tend to hold it in the
direction of the sun. The result will be an electrospheric libration,
so to speak, and the moon's atmosphere and moisture will be carried
around towards its illuminated face and, to some extent, will overlap
the area of terrestrial repulsion. But as the moon advances this will
gradually diminish, soon cease, and finally be reversed as it again
approaches darkness. We can now understand why the green surface, if
it really was due to vegetation, appeared along the lunar margin at
the time described above, and also that the observation of planetary
occultations "at the unilluminated edge of the young moon" was the
very worst part of the moon and its orbit in which to look for air
or moisture; as the sun's influence is then directly away from the
unilluminated surface of the moon, and his "pull" would have, in fact,
still further denuded the very portion most persistently examined,
and where this absence of atmosphere was especially noted.
When considering the transference of energy from the peripheral
regions of the solar system to the center, its conversion there into
a new form of molecular force, and its subsequent distribution, we
find a curious and instructive parallel in the action of the reflex
nervous system of animal life. This system is one in which the brain
or other conscious center of nerve-energy takes no part. Tickle
the foot of a child, for example, and its whole muscular system is
thrown into uncontrollable convulsions of laughter. Here an exciting
contact with the terminal filaments of the afferent or sensory nerves
is rapidly carried into the local nerve-center of this part of the
system,--that is, the sensory column of the spinal cord. This center
of ganglionic nerve-matter lies directly against the corresponding
motor mass, both freely communicating with each other. The sensory
current passing into its central ganglion undergoes some peculiar
change of character, probably one of intensification, such as is
observed in the action of the condenser of an electrical machine,
through which sensory ganglion, thus raised in potential, it passes to
the motor ganglion adjacent, where it is instantly transformed into
an entirely different form of energy. The sensory character has now
entirely disappeared, and it has been converted into and is flashed
forth as motor energy to the different muscles of the body, which are
immediately contracted, the violent molecular motion of the fibres
being at once converted into muscular motion in mass. The changes are
entirely analogous to those we see in the different conversions of
energy in our solar system. Considering the surface of the body as a
planetary electrosphere, it is acted upon by excitation from without;
currents of energy are engendered, which are at once transmitted to
the sensory ganglion, corresponding to the hydrogen atmosphere or
electrosphere of the sun; intensification of action here ensues, the
current passing through this ganglion or atmosphere into the solar body
itself, which corresponds to the motor ganglion; both ganglia are now
highly excited; the electrical force is converted into the radiant
molecular motor energy of heat and light in the sun and muscular
excitement in the body, and these are flashed forth and find scope
for their action within the body of the subject or upon the surface
of the planets, which lie, like the muscular structure of the body,
within the genetic electrosphere where, acted upon from without and
by agencies entirely external, moving contact has induced the primary
molecular action, which was then instantaneously transferred to the
center, there converted into another form, that of motor energy,
and thence sent forth to produce action in the muscles of the body
in the one case, and in the other upon the planetary bodies and their
satellites and other structures which occupy surrounding space.