Meteors
Mr. Denning thinks that the meteor shower of the month of May, known as
the Aquarids, is probably connected with Halley's comet. The meteors
should be looked for after 1 a.m. during the first week in May, and may
possibly show an enhanced display in May, 1910, when Halley's comet will
be near the sun and earth.[231]
On November 29, 1905, Sir David Gill observed a fireball with an apparent
diameter equal to that of the moon, which remained visible for 5 minutes
and disappeared in a hazy sky. Observed from another place, Mr. Fuller
found that the meteor was visible 2 hours later! Sir David Gill stated
that he does not know of any similar phenomenon.[232]
Mr. Denning finds that swiftly moving meteors become visible at a greater
height above the earth's surface than the slower ones. Thus, for the
Leonids and Perseids, which are both swift, it has been found that the
Leonids appear at an average height of 84 miles, and disappear at a height
of 56 miles; and the Perseids at 80 and 54 miles respectively. "On the
other hand, the mean height of the very slow meteors average about 65
miles at the beginning and 38 miles at the end of their appearance."[233]
During the night of July 21-22, 1896, Mr. William Brooks, the well-known
astronomer, and director of the Smith Observatory at Geneva (New York),
saw a round dark body pass slowly across the moon's bright disc, the moon
being nearly full at the time. The apparent diameter of the object was
about one minute of arc, and the duration of the transit 3 or 4 seconds,
the direction of motion being from east to west. On August 22 of the same
year, Mr. Gathman (an American observer) saw a meteor crossing the _sun's_
disc, the transit lasting about 8 seconds.[234]
A meteor which appeared in Italy on July 7, 1892, was shown by Prof. von
Niessl to have had an _ascending_ path towards the latter end of its
course! The length of its path was computed to be 683 miles. When first
seen, its height above the earth was about 42 miles, and when it
disappeared its height had increased to about 98 miles, showing that its
motion was directed upwards![235]
In the case of the fall of meteoric stones, which occasionally occur, it
has sometimes been noticed that the sound caused by the explosion of the
meteorite, or its passage through the air, is heard before the meteorite
is seen to fall. This has been explained by the fact that owing to the
resistance of the air to a body moving at first with a high velocity its
speed is so reduced that it strikes the earth with a velocity less than
that of sound. Hence the sound reaches the earth before the body strikes
the ground.[236]
The largest meteoric stone preserved in a museum is that known as the
Anighita, which weighs 36-1/2 tons, and was found at Cape York in
Greenland. It was brought to the American Museum of Natural History by
Commander R. E. Peary, the Arctic explorer.
The second largest known is that of Bacubirito in Mexico, the weight of
which is estimated at 27-1/2 tons.
The third largest is that known as the Williamette, which was found in
1902 near the town of that name in Western Oregon (U.S.A.). It is composed
of metallic nickel-iron, and weighs about 13-1/2 tons. It is now in the
American Museum of Natural History.
A large meteorite was actually seen, from the deck of the steamer _African
Prince_, to fall into the Atlantic Ocean, on October 7, 1906! The captain
of the vessel, Captain Anderson, describes it as having a train of light
resembling "an immense broad electric-coloured band, gradually turning to
orange, and then to the colour of molten metal. When the meteor came into
the denser atmosphere close to the earth, it appeared, as nearly as is
possible to describe it, like a molten mass of metal being poured out. It
entered the water with a hissing noise close to the ship."[237] This was a
very curious and perhaps unique phenomenon, and it would seem that the
vessel had a narrow escape from destruction.
In Central Arizona (U.S.A.) there is a hill called Coon Butte, or Coon
Mountain. This so-called "mountain" rises to a height of only 130 to 160
feet above the surrounding plain, and has on its top a crater of 530 to
560 feet deep; the bottom of the crater--which is dry--being thus 400 feet
below the level of the surrounding country. This so-called "crater" is
almost circular and nearly three-quarters of a mile in diameter. It has
been suggested that this "crater" was formed by the fall of an enormous
iron meteorite, or small asteroid. The "crater" has been carefully
examined by a geologist and a physicist. From the evidence and facts
found, the geologist (Mr. Barringer) states that "they do not leave, in my
mind, a scintilla of doubt that this mountain and its crater were produced
by the impact of a huge meteorite or small asteroid." The physicist (Mr.
Tilghmann) says that he "is justified, under due reserve as to
subsequently developed facts, in announcing that the formation at this
locality is due to the impact of a meteor of enormous and unprecedented
size." There are numerous masses of meteoric iron in the vicinity of the
"crater." The so-called Canyon Diabolo meteorite was found in a canyon of
that name about 2-1/2 miles from the Coon Mountain. The investigators
estimate that the great meteoric fall took place "not more than 5000 years
ago, perhaps much less." Cedar trees about 700 years old are now growing
on the rim of the mountain. From the results of artillery experiments, Mr.
Gilbert finds that "a spherical projectile striking solid limestone with a
velocity of 1800 feet a second will penetrate to a depth of something less
than two diameters," and from this Mr. L. Fletcher concludes "that a
meteorite of large size would not be prevented by the earth's atmosphere
from having a penetration effect sufficient for the production of such a
crater."[238]
The meteoric origin of this remarkable "crater" is strongly favoured by
Mr. G. P. Merrill, Head Curator of Geology, U.S. National Museum.
The Canyon Diabolo meteorite above referred to was found to contain
diamonds! some black, others transparent. So some have said that "the
diamond is a gift from Heaven," conveyed to earth in meteoric
showers.[239] But diamond-bearing meteorites would seem to be rather a
freak of nature. It does not follow that _all_ diamonds had their origin
in meteoric stones. The mineral known as periodot is frequently found in
meteoric stones, but it is also a constituent of terrestrial rocks.
In the year 1882 it was stated by Dr. Halm and Dr. Weinhand that they had
found fossil sponges, corals, and crinoids in meteoric stones! Dr.
Weinhand thought he had actually determined three genera![240] But this
startling result was flatly contradicted by Carl Vogt, who stated that the
supposed fossils are merely crystalline conformations.[241]
Some meteorites contain a large quantity of occluded gases, hydrogen,
helium, and carbon oxides. It is stated that Dr. Odling once "lighted up
the theatre of the Royal Institution with gas brought down from
interstellar space by meteorites"![242]
On February 10, 1896, a large meteorite burst over Madrid with a loud
report. The concussion was so great that many windows in the city were
broken, and some partitions in houses were shaken down![243]
A very brilliant meteor or fireball was seen in daylight on June 9, 1900,
at 2{h} 55{m} p.m. from various places in Surrey, Sussex, and near London.
Calculations showed that "the meteor began 59 miles in height over a point
10 miles east of Valognes, near Cherbourg, France. Meteor ended 23 miles
in height, over Calais, France. Length of path 175 miles. Radiant point,
280°, 12°."[244]
It was decided some years ago "in the American Supreme Court that a
meteorite, though a stone fallen from heaven, belongs to the owner of the
freehold interest in the land on which it falls, and not to the
tenant."[245]
With reference to the fall of meteoric matter on the earth, Mr. Proctor
says, "It is calculated by Dr. Kleiber of St. Petersburgh that 4250 lbs.
of meteoric dust fall on the earth every hour--that is, 59 tons a day, and
more than 11,435 tons a year. I believe this to be considerably short of
the truth. It sounds like a large annual growth, and the downfall of such
an enormous mass of meteoric matter seems suggestive of some degree of
danger. But in reality, Dr. Kleiber's estimate gives only about 25
millions of pounds annually, which is less than 2 ounces annually to each
square mile of the earth's surface,"[246] a quantity which is, of course,
quite insignificant.
According to Humboldt, Chladni states that a Franciscan monk was killed by
the fall of an aërolite at Milan in the year 1660.[247] Humboldt also
mentions the death by meteoric stones of a monk at Crema on September 4,
1511, and two Swedish sailors on board ship in 1674.[248]
It is a curious fact that, according to Olbers, "no fossil meteoric
stones" have ever been discovered.[249] Considering the number which are
supposed to have fallen to the earth in the course of ages, this fact
seems a remarkable one.
On May 10, 1879, a shower of meteorites fell at Eitherville, Iowa
(U.S.A.). Some of the fragments found weighed 437, 170, 92-1/2, 28,
10-1/2, 4 and 2 lbs. in weight. In the following year (1880) when the
prairie grass had been consumed by a fire, about "5000 pieces were found
from the size of a pin to a pound in weight."[250]
According to Prof. Silvestria of Catania, a shower of meteoric dust mixed
with rain fell on the night of March 29, 1880. The dust contained a large
proportion of iron in the metallic state. In size the particles varied
from a tenth to a hundredth of a millimetre.[251]
It is sometimes stated that the average mass of a "shooting star" is only
a few grains. But from comparisons with an electric arc light, Prof. W.
H. Pickering concludes that a meteor as bright as a third magnitude star,
composed of iron or stone, would probably have a diameter of 6 or 7
inches. An average bright fireball would perhaps measure 5 or 6 feet in
diameter.[252]
In the Book of Joshua we are told "that the LORD cast down great stones
from heaven upon them unto Azekah, and they died" (Joshua x. 11). In the
latter portion of the verse "hailstones" are mentioned, but as the
original Hebrew word means stones in general (not hailstones), it seems
very probable that the stones referred to were aërolites.[253]
The stone mentioned in the Acts of the Apostles, from which was found "the
_image_ which fell down from Jupiter" (Acts xix. 35), was evidently a
meteoric stone.[253]
The famous stone in the Caaba at Mecca, is probably a stone of meteoric
origin.[253]
I
"Stones from Heaven! Can you wonder,
You who scrutinize the Earth,
At the love and veneration
They received before the birth
Of our scientific methods?
II
"Stones from Heaven! we can handle
Fragments fallen from realms of Space;
Oh! the marvel and the mystery,
Could we understand their place
In the scheme of things created!
III
"Stones from Heaven! With a mighty
Comet whirling formed they part?
Fell they from their lofty station
Like a brilliant fiery dart,
Hurl'd from starry fields of Night?"[254]