Evening star. [volume] (Washington, D.C.) 1854-1972, 1890-02-10
SOLAR PHENOMENA.
Fountains of Fire on Which the Eartl
Could Dance Like a Cork.

I
heat and dazzling radiance Of which we tried
to obtain some idea last week? Some have held
that the supply Of heat is kept up by meteors
| falling from space. II a mass of meteoric
matter the size of the earth should fall into
| the sun the powerful force of gravitation ex-
! erted by that body would cause it to acquire
| before striking a rapidity of over 80 miles a
| second If such a mass should fall into the
| sun once in a century. even in small pieces
] few at time, it would suffice to main-
| tain the sun at the same temperature
which it now possesses. But If the quantity
| Of meteoric matter flying about in space
were as large this theory would require we
| would have evidence of it in the character of
the meteoric showers upon our planet. True,
| the sun would catch more of this kind of fish
In proportion to its superficial area than we
would do, having more powerful bait in it's
great bulk and proportionate force of grayita-
| ton. But if the meteor hypothesis were true
such a number would fall upon the earths sur
face as to lmpart to it at least half as much
heat as it receives from the sun, and the
weight or the meteors reaching US annually
would average about 2S1z tons to each acre Of
the earth's surface. The city bureau Of street
cleaning in New York might not notice this
little accumulation of meteors in their streets,
but the farmers certainly would in their fields
Laughter and applause.l 1t is true, quite
probably, that there is ring or sk-shaped
mass of meteors revolving near the sun and
that we see II edgewise, in what is called the
zodiacal light. This may be observed immedi-
ately after sunset in March and before sunrise
In september. The meteoric theory of the
sun heat Is now generally abandoned and an
other that OF HelmholtZ, is accepted and seems
certainly more probable. According to this the
DRY the heat is causedb a steady contraction of
the suns mass, a contraction amply sufficient
to account for all the solar heat, but not enough
to have been noticeable within historic times.
FROM this theory we may also conclude that
as far as any natural causes are concerned the
heat Of the sun will last for millions Of years.
SOLAR ECLIPsEs.
Going on to the subject of solar eclipses the
lecturer said that the sun and the moon appear
to Us about the same size because, although
the sun is 400, 900 times farther away than the
moon, its diameter is about 100000 times
greater. But the distances of the sun and moon
vary at different times. Their apparent sizes.
therefore, though averaging the same some
times differ relatively to each other When
the moon is far off and the sun is near, the sun
would have the advantage in apparent size, and
wee versa Strange to say, the sun is farthest
on In summer and nearest in winter. On the
LIST Of January the sun looks bigger than on any
other day IN the year. When the eclipse comes
at time when the sun is farthest away and the
moon nearest, the disk of the moon hides the
sun entirely from view. This is called a total
eclipse. When the moon is farther away and
the sun nearer the moon appears the smaller of
the two and Is entirely surrounded by the SUM-
This is called an annular or ring-shaped
eclipse. When the moon is off little
to one side 1t is called partial
eclipse. Total eclipses are more common
between April and October than between Octo-
Der and April. Even during total eclipses it is
not as dark as at night. This is accounted for
partly by the fact that although we NAV be in the
center OF the moons shadow we can see some
AIR outside OF the limits, from which some light
is reflected, and partly on account of the suns
corona, which We see as an irreguiarly shaped
radiance streaming out from the border of the
moon. This does not appear of the same shape
IN different observations. In 1869 it was seen
In the form OF cross with four more or less
distinct eiongations. In 1878 it appeared very
nearly circular. Certain peculiar rays which
arise from it would seem to indicate some cleo
trlc or magnetic action. 1t must be composed
OF very attenuated matter, for comets have
passed through 1t without being perceptibly re-
tarded in their course. In the Egyptian eclipse
OF 1882 comet never seen before nor since
WAS photographed accidentally very near to the
corona.
Sun SPOTS AND ''PRoM1NEScEs."
Not much is known about the corona and
the principle object of the numerous expedi-
tons for the observation of eclipses is the in
crease Of our knowledge regarding this phe-
nomenon. which cannot be studied at any other
time. There are, impinging on the inner edge
OF the corona, certain projections of a very
bright red color, which were first called flames.
afterward protuberances and now promi-
nences. Strangely enough they never seem to
have attracted special attention in the early
recorded observations. They are much more
conspicuous in some ecipses than Others In
the eclipse of 1869 they were the first things to
attract attention. great deal more is known
about these prominences than about the cor ona
They can be studied to the best advantage out
side OF eclipses, for by special apparatus, to be
described later, We may make them visible at
any time. The prominences seem to have
some connection with the spots. Sometimes,
when we can follow out the spots pretty well.
they seem to turn into prominences when they
reach the edge Of the sun. 1t is safe to saw
that these prOmlnences, especially those of the
eruptIve kind, are in the places where the great
est disturbances exist. The prominences range
however, from one pole of the sun to the other
while spots only occur in the sub-equatorial re-
gions. The prominences may be divided into
two classes, the qulescent and the eruptiye
The quiescent may be the result of the erup-
tive, just as the smoke of a volcano may re-
main after the eruption has ceased. Some of
the quiescent prominences appear like Clouds
wholly disconnected from the suns substance
which indicates the presence of an atmosphere
In which they seem to condenbe. Usually.
however, they are resting on the surface Of the
sun, or bearing evidence of soIne connection
with 1t by stem or the remains of one.
They change their shape very slowly, are not
very brilliant and seem to be rather cold. The
eruptive ones are much more interesting on
account of the rapidity Of their changes. The
eruptive protuberances are shown by the spec
troscope to consist principally OF hydrogen gas
rather than of carbon, with which flames in the
earth are associated. The shapes OF the prom
inences are very various, the hame-like, foun-
tain-like, rocket-shaped and spiral or cyclonic
being among the more constantly recurring
forms. Two observations upon one of these
objects, forty-hve minutes apart. showed it to
have increased in that time from 50. 900 miles
to zoo, 600 miles in height. mass of hydrogen
gas with dimensions Of 5000 by 80, 900 miles.
and probably $4,000 miles thick. had been
blown to pieces and hoisted to this stupendous
elevation.
COLOSSAL FORCES.
Another protuDerance appears before the
telescope as an enormous fountain of fiery gas.
Now just think of this stupendous thing a mo-
ment and try to realize it, if it be possible to
form conception so far transcending human
experience. There might be dropped on this
fountain our whole globe, with ali its CONT
nents and islands, its rivers and mighty oceans,
Its countries and empires; and this great planet
II IL could be preserved from being almost in
stantly melted to yapor in the fearful heat
would leap and play on the top of this tremen-
dous fountain as you have often seen cork bail
do on the top of "A fountain in one OF our city
parks. The imagination wesries itself in trying
10 picture such colossal forces. Truly the
heavens declare the power and the glory of
God; and yet these things, we shall soon be
convinced, are only the beginning of their
wonders.
The subject of the next lecture, which will
be given ON Friday, the 14th instant, at 4:45
clock, will be the spectroscope and its appi-