Evening star. [volume] (Washington, D.C.) 1854-1972, 1889-02-09

| no time after the panic at Bull Run could the
confederstes, though they should gain posses
! sion Of Arlington Heights, have crossed the Po-
tomac in front Of Washington. for our gun-
boats in the river would have swept them in
| the flank and destroyed them while crossing
these gunboats thus constituted an impreg-
nabie defense of our national capital in front
during the whole war, so that the enemy could
seriously threaten it only in rear, and that
tions."
written for The EVENING STAR.
COMETS AND METEORS.
A Few Facts About these Celestial
Visitors and their Relationship.
There are few persons who have not wit
messed the striking phenomena of the so-called
shooting stars" They are visible any clear
| night, and with a little patient observation
several may be seen during an evening. Flash
ing out in various quarters of the heavens, they
| are seen to dart across the sky with motions
more or less rapid, and with brilliancy more or
| less marked, some down towards mother earth,
others across the starry arch, leaving behind
| them phosphorescent glow generally visible
| only for moment. Larger meteors land the
term at this stage can only be used in express
ing their size by their light often leave be-
hind them a very marked glow, much like a
| faint cloud, and which when the meteor's flight
is thus marked, usually remains suspended in
the sky for some considerable time. The
writer saw such a meteor on the night of Au-
gust 3, 1888, which left in its path a greenish
| glow, visible to the naked eve for fully twenty
minutes. Such occurrences are rare, however,
| and few are witnessed in lifetime. Instances
! are on record of meteoric showers visible in
broad daylight, and well-attested statements
have been made of single meteors OF great size
seen to fall in various parts of the country be-
tween sunrise and sunset.
WONDERFUL srETEoRIc SHOWERS.
Meteoric showers have in numerous in
stances been so marvellous that the fall pre-
sented an appearance like that of light fall
OF illuminated snow. One of the earliest of
recorded phenomena of this character and
which is well attested, was witnessed bv Hum
boldt and Bonpland early on the morning of
November II, 1899, during their visit to the
east coast Of Mexico. Another well-attested
statement is that of Arago, the well-known
astronomer s who on the night of November -,
1883 (and here note that both occurred on the
same day of the same month, and divided by a
space OF thirty-four years., witnessed such
marvellous shower that he estimated that dur
ing his observation of three hours 240, 900 visi-
BILE meteors passed over the heavens A rough
estimate of the number of meteors, sufficiently
bright to be seen by the naked eye under fav-
orable circumstances, and those invisible.
owing to the daylight, and which enter the
eartn atmosphere during the space of twenty
four hours, is about 1000, 900. Some we'll
known scientists. taking into consideration
those which would be revealed if the eye pos
sessed the light-grasping power of our larger
telescopes, increase that number to about
4oO,OOO,OOO. We often hear of the falling of
''GREAr BALLS OF FIRE."
with startling explosions following. Scientists
tell us that these so-called balls of fire are
really compact groups of small meteors. When
such group comes within tho attraction of
the earth 1t is drawn rapidly toward her sur
race. The encounter with the atmosphere
separates them and at the same time consumes
them, producing no little agitation of the air.
| and thus causing the sound. This action of
separation and burning would give a result in
some cases much like that of a rocket explod-
ing in the air, with which display all are famil-
lar.
SHOWERS OF STONES
Instances Of meteoric bodies falling to earth
are comparatively rare. To enable it to reach
the earth the mass of matter composing meteor
must be OF sufficient bulk to prevent complete
dissipation or consumption during its passage
through the atmosphere to earth. However
showers Of stones are matters of history On
the 26th of April, 1903, such shower occurred
at L'Aigle, in Normandy. The number of
meteoric stones found within a space of IA
square miles was over 1000 This fan was ac-
companled by "bright light and loud explo-
sions." The height at which meteors first appear
visible is much-disputed question. Estimates
made by well-known observers give results
varying from 40 to 80 miles; the average
velocity accorded them being about % miles
per second or nearly half as fast again as the
earth travels around the sun. Some meteors.
however, have been obsewed to possess
velocity OF over 100 miles per second, or
| THREE HUNDRED AND SIXTY THOUSAND MILES PER
HOUR!
Perhaps the reader will ask: 'Why are these
bodies burned up?" The answer is this: SUD-
pose two bodies moving in space with such
great velocity and in independent orbits en-
COUNTER what will be the result? A sudden
check OF their motion converts that motion
into heat This rule applies in all cases. In
the case OF the earth and the meteors the
action is identical. The mean rate of motion
of the earth in her orbit is about nineteen
miles per second. Moving along at this rate
she encounters cloud of meteors whose
motion is further increased by the attraction
Of the greater body. The cloud of meteors
encounters resistance in the earth's atmos-
phere and the friction produced converts the
motion into heat SO great that the meteoric
heat is generated in the earth's atmosphere. as
its share OF the encounter, but the relative
amount to the bulk, or quantity, is trifing. II
is stated that the amount Of heat ordinarily
ueVeIOpeu Dy the ABOVE described encounter ia
enough to vaporize any known substance al
most instantly! The fact that the greater num-
Der OF meteors are consumed and disappear
before they reach the earth is sufficient evil
dence that their mass is small Such of these
meteoric visitors as have been discovered on
the surface of the earth and afterward an
alyzed show, in general, only terrestrial ele-
ments.
DISTINCTION Is MADE
between accidental meteors' and "meteoric
showers" As relates to the first named, their
visibility is common at all times and might be
called accidental because they usually ap-
pear in widely different quarters of the sky
and possess widely different paths ssMeteoric
showers make their appearance in certain
portions of the sky-that Is they appear TO ra-
date always from some particular constella-
ton. These showers always take place on
certain nights of August and November of
every year. It is believed. from the fact that
they occur annually, that the meteors causing
them revolve in orbits around our sun, and in
tersect the earth's orbit at points reached by
her in August and November. Further, that
these rings OF meteors are of varying thickness
at different points, giving us showers of vary
ing splendor. The greatest display by the
November meteors takes place every thirty
three years. The orbits of the August and
November meteors have been calculated by
Leverier and others, who discovered the
WONDERFUL RELATIONSHIP BETWEEN MErxoRs
AND COMETS.