This time we may fairly expect some approach to a solution of the
riddle of the corona, as the one essential which neither scientific
skill nor Government liberality could secure to the eclipse observers,
has been afforded, viz., fine weather. The telegraph has already
informed us of this, and also that good use has been made of the
good weather. From one station we are told: “Thin mist; spectroscope
satisfactory; reversion of lines entirely confirmed; six good
photographs.” From another: “Weather fine; telescopic and camera
photographs successful; ditto polarization; good sketches; many bright
lines in spectrum.”
This is very different from the gloomy accounts of the expedition of
last year; when we consider that the different observers are far apart,
and that if all or some of them are similarly favored we shall have in
the photographs a series of successive pictures taken at intervals of
time sufficiently distant to reveal any progressive changes that may
have occurred in the corona while the moon’s shadow was passing from
one station to the other. I anticipate some curious revelations from
these progressive photographs, that may possibly reconcile the wide
differences in the descriptions that competent observers have given of
the corona of former eclipses, which they had seen at stations distant
from each other.
Barely two years have elapsed since I suggested, in “The Fuel of the
Sun,” that the great solar prominences and the corona are due to
violent explosions of the dissociated elements of water; that the
prominences are the gaseous flashes, and the corona the ejected scoria,
or solidified metallic matter belched forth by the furious cannonade
continually in progress over the greater portion of the solar surface.
This explanation at first appeared extravagant, especially as it was
carried so far as to suggest that not merely the corona, but the
zodiacal light, the zone of meteors which occasionally drop showers of
solid matter upon the earth, and even the “pocket-planets” or asteroids
so irregularly scattered between the orbits of Mars and Jupiter,
consist of solid matter thus ejected by the great solar eruptions.
Even up to the spring of the present year, when Mr. Lockyer and other
leaders of the last year’s expeditions reported their imperfect
results, and compared them with various theories, this one was not
thought worthy of their attention.
Since that time—during the past six or eight months—a change has
taken place which strikingly illustrates the rapid progress of solar
discovery. Observations and calculations of the force and velocity of
particular solar eruptions have been made, and the results have proved
that they are amply sufficient to eject solid missiles even further
than I supposed them to be carried.
Mr. Proctor, basing his calculations upon the observations of Respighi,
Zöllner, and Professor Young, has concluded that it is even possible
that meteoric matter may be ejected far beyond the limits of our solar
system into the domain of the gravitation of other stars, and that
other stars may in like manner bombard the sun.
This appears rather startling; but, as I have already said, the
imagination of the poet and the novelist is beggared by the facts
revealed by the microscope, so I may now repeat the assertion, and
state it still more strongly, in reference to the revelations of the
telescope and the spectroscope.
As a sample of these, I take the observations of Professor Young, made
on September 7th last, and described fully in “Nature” on October 19.
He first observed a number of the usual flame-prominences having the
typical form which has been compared to a “banyan grove.” One of
these banyans was greater than the rest. This monarch of the solar
flame-forest measured _fifty-four thousand miles in height_, and its
outspreading measured in one direction about _one hundred thousand
miles_. It was a large eruption-flame, but others much larger have been
observed, and Professor Young would probably have merely noted it among
the rest, had not something further occurred. He was called away for
twenty-five minutes, and when he returned “the whole thing had been
literally blown to shreds by some inconceivable uprush from beneath.”
The space around “was filled with flying _débris_—a mass of detached
vertical fusiform filaments, each from 10 sec. to 30 sec. long by 2
sec. or 3 sec. wide, brighter and closer together where the pillars had
formerly stood, _and rapidly ascending_.” Professor Young goes on to
say, that “When I first looked, some of them had already reached a
height of 100,000 miles, and while I watched they rose, with a motion
almost perceptible to the eye, until in ten minutes the uppermost were
200,000 miles above the solar surface. This was ascertained by careful
measurement.”
Here, then, we have an observed velocity of 10,000 miles per minute,
and this is the gaseous matter, merely the flash of the gun by which
the particles of solidified solar matter are supposed to be projected.
The reader must pause and reflect, in order to form an adequate
conception of the magnitudes here treated—100,000 miles long and
54,000 miles high! What does this mean? Twelve and a half of our worlds
placed side by side to measure the length, and six and three quarters,
piled upon each other, to measure the height! A few hundred worlds as
large as ours would be required to fill up the whole cubic contents of
this flame-cloud. The spectroscope has shown that these prominences
are incandescent hydrogen. Most of my readers have probably seen a
soap-bubble or a bladder filled with the separated elements of water,
and then exploded, and have felt the ringing in their ears that has
followed the violent detonation.
Let them struggle with the conception of such a bubble or bladder
magnified to the dimensions of only one such a world as ours, and
then exploded; let them strain their power of imagination even to the
splitting point, and still they must fail most pitifully to picture
the magnitude of this solar explosion observed on September 7th last,
which flashed out to a magnitude of more than five hundred worlds,
and then expanded to the size of more than five thousand worlds, even
while Professor Young was watching it. Professor Young concludes his
description by stating that “it seems far from impossible that the
mysterious coronal streamers, if they turn out to be truly solar, as
now seems likely, may find their origin and explanation in such events.”
This, and a number of similar admissions, suggestions, and conclusions
from the leading astronomers, indicate that the eruption theory of the
corona will not be passed over in silence by the observers of this
eclipse, and it is to this that I have referred in the above remarks
respecting the interest attaching to a series of photographs showing
successive states of this outspreading enigma.
Father Secchi’s spectroscopic observations on the uneclipsed sun led
him to assert the existence of a stratum of glowing metallic vapors
immediately below the envelope connected with the hydrogen of the
eruptions. This is just what is required by my eruption theory to
supply the solid materials of the ejections forming the corona.
Professor Young’s announcement of the reversal of the spectroscopic
lines at the moment when the stratum was seen independently of the
general solar glare, startled Mr. Lockyer and others who had disputed
the accuracy of the observations of the great Italian observer, as it
confirmed them so completely. Scepticism still prevailed, and Young’s
observation was questioned; but now even our slender telegraphic
communication from Colonel Tenant to Dr. Huggins indicates that the
question must be no longer contested. “Reversion of lines entirely
confirmed” is a message so important that if the expeditions had done
no more than this, all their cost in money and scientific labor would
be amply repaid in the estimation of those who understand the value of
pure truth.
A few more fragments of intelligence respecting the Eclipse Expedition
have reached us, the last Indian mail having started just after
the eclipse occurred. They fully confirm the first telegraphic
announcement, rather strengthening than otherwise the expectations of
important results, especially in reference to the photographs of the
corona.
I have read in the Ceylon newspapers some full descriptions by amateur
observers, in which the general magnificence of the phenomena is
described. From these it is evident that the corona must have been
displayed in its full grandeur; but as the writers do not attempt to
describe those features which have at the present moment a special
scientific interest, I shall not dwell upon them, but await the
publication of the official report of the chief, and of the more
important collateral observing expeditions.
The unsophisticated reader may say “Are not one man’s eyes as good as
another’s, and why should the observations of the learned men of the
expeditions be so much better than those of any other clear-sighted
persons?” This is a perfectly fair question, and admits of a ready
answer. All that can be known by mere unprepared naked-eye observation
is tolerably well known already; the questions which await solution can
only be answered by putting the sun to torture by means of instruments
specially devised for that purpose; and by a skillful organization, and
division of labor among the observers.
There is so much to be seen during the few seconds of total obscuration
that no one human being, however well trained in the art of observing,
could possibly see all. Therefore it is necessary to pre-arrange each
observer’s part, to have careful rehearsals of what is to be done by
each during the precious seconds; and each man must exercise a vast
amount of self-control in order to confine his attention to his own
particular bit of observation, while he is surrounded with such
marvellous phenomena as a total eclipse presents.
The grandeur of the gloomy landscape, the sudden starting out of the
greater stars, the seeming falling of the vault of heaven, the silence
of the animal world, the closing of the flowers, and all that the
ordinary observer would regard with so much awe and wondering delight,
must be sacrificed by the philosopher, whose business is to confine
his gaze to a narrow slit between two strips of metal, and to watch
nothing else but the exact position and appearance of a few bright or
dark lines across what appears but a strip of colored riband. He must
resist the temptation to look aside and around with the stubbornness of
self-denial of another St. Antonio. Besides this, he must thoroughly
understand exactly what to look for, and how to find it. By combining
the results of his observations with those of the others, who in like
manner have undertaken to work with another instrument, or upon another
part of the phenomena, we get a scientific result comparable to that
which in a manufactory we obtain by the division of labor of many
skilled workmen, each doing only that which by his training he has
learned to do the best and the most expeditiously.