254. I haave very recently endeavored to show, in another work ('Asie
Centrale', t. i., p. 408). how the Scythian saga of the sacred gold, which
fell burning from heaven, and remained in the possession of the Golden Horde
of the Paralatæ (Herod., iv., 5-7), probably originated in the vague
recollection of the fall of an aërolite. The ancients had also some
strange fictions (Dio Cassius, lxxv., 1259) or silver which had fallen from
heaven, and with which it had been attempted, under the Emperor Severus, to
cover bronze coins; metallic iron was however, known to exist in meteoric
stones. (Plin., ii., 56.) The frequently-recurring expression 'lapidibus
pluit' must not always be understood to refer to falls of aërolites. In
Liv., xxv., 7, it probably refers to pumice ('rapilli') ejected from the
volcano, Mount Albanus (Monte Cavo), which was not wholly extinguished at
the time. (See Heyne, 'Opuscula Acad.', t. iii., p. 261; and my 'Relation
Hist.', t. i., p. 394.) The contest of Hercules with the Ligyans, on the
road from the Caucasus to the Hesperides, belongs to a different sphere of
ideas, being an attempt to explain mythically the origin of the round quartz
blocks in the Ligyan field of stones at the mouth of the Rhone, which
Aristotle supposes to have been ejected from a fissure during an earthquake,
and Posidonius to have been caused by the force of the waves of an inland
piece of water. In the fragments that we still possess of the play of
Æschylus, the 'Prometheus Delivered', every thing proceeds, however, in
part of the narration, as in a fall of aërolites, for Jupiter draws
together a cloud, and causes the "district around to be covered by a shower
of round stones". Posidonius even ventured to deride the geognostic myth of
the blocks and stones. The Lygian field of stones was, however, very
naturally and well described by the ancients. The district is now known as
'La Crau.' (See Guerin, 'Mesures Barométriques dans les Alpes, et
Météorologie d'Avignon', 1829, chap. xii., p. 115.)
p 116
We can ascertain by measurement the enormous, wonderful, and wholly
planetary velocity of shooting stars, fire-valls and meteoric stones, and we
can gain a knowledge of what is the general and uniform character of the
phenomenon, but not of the genetically cosmical process and the results of
the metamorphoses. If meteoric stones while revolving in space are already
consolidated into dense masses,* less dense, however,
p 117
than the mean density of the earth, they must be very small nuclei, which
surrounded by inflammable vapor or gas, form the innermost part of
fire-balls, from the height and apparent diameter of which we may, in the
case of the largest, estimate that the actual diameter varies from 500 to
about 2800 feet.
[footnote] *The specific weight of aërolites varies from 1.9 (Alais) to 4.3
(Tabor). Their general density may be set down as 3, water being 1. As to
what has been said in the text of the actual diameters of fire-balls, we
must remark, that the numbers have been taken from the few measurements that
can be relied upon as correct. These give for the fire-ball of Weston,
Connecticut (14th December, 1807), only 500; for that observed by Le Roi
(10th July, 1771) about 1000 and for that estimated by Sir Charles Blagden
(18th January, 1783) 2600 feet in diameter. Brandes ('Unterhaltungen'
bd.i., s. 42) ascribes a diameter varying from 80 to 120 feet to shooting
stars, and a luminous train extending from 12 to 16 miles. There are,
however, ample optical causes for supposing that the apparent diameter of
fire-balls and shooting stars has been very much overrated. The volume of
the largest fire-ball yet observed can not be compared with that of Ceres,
estimating generally so exact and admirable treatise, 'On the Connection of
the Physical Sciences', 1835, p. 411.) With the view of elucidating what
has been stated in the text regarding the large zërolite that fell into the
bed of the River Narni, but has not again been found, I will give the
passage made known by Pertz, from the 'Chronicon Benedicti, Monachi Sancti
Andreæ in Mont Soracte', a MS. belonging to the tenth century, and
preserved in the Chigi Library at Rome. The Barbarous Latin of that age has
been left unchanged. "Anno 921, temporibus domini Johannis Decimi pape, in
anno pontificatus illius 7 visa sunt signa. Nam juxta urben Romam lapides
plurimi de cælo cadere visi sunt. In civilate quæ vocatur Narnia tam diri
ac tetri, ut nihil aliud credatur, quam de infernalibus locis deducti
essent. Nam ita ex illis lapidibus unus omnium maximum est, ut decidens in
flumen Narnus, ad mensuram unius cubiti super aquas fluminus usque hodie
videretur. Nam et ignitæita ut pene terra contingeret. AliAnno 921,
temporibus domini Johannis Decimi pape, in anno pontificatus illius 7 visa
sunt signa. Nam juxta urben Romam lapides plurimi de cælo cadere visi
sunt. In civilate quæ vocatur Narnia tam diri ac tetri, ut nihil aliud
credatur, quam de infernalibus locis deducti essent. Nam ita ex illis
lapidibus unus omnium maximum est, ut decidens in flumen Narnus, ad mensuram
unius cubiti super aquas fluminus usque hodie videretur. Nam et ignitæ ita
ut pene terra contingeret. Ali cadentes," etc. (Pertz, 'Monum. Germ. Hist.
Scriptores', t. iii., p. 715.) On the aërolites of gos Potamus, which
fell, according to the Parian Chroniccle, in the 78 1 Olympiad, see Böckh,
'Corp. Inscr. Graec', t. ii., p. 302, 320, 340; also Aristot., 'Meteor.',
i., 7 (Ideler's 'Comm.', t. i., p. 404-407); Stob., 'Eel. Phys.', i., 25, p.
508 (Heeren); Plut., 'Lys.', c. 12; Diog. Laert., ii., 10; and see, also,
subsequent notes in this work. According to a Mongolisn tradition, a black
fragment of a rock, forty feet in height, fell from heaven on a plain near
the source of the Great Yellow River in Western China. (Abel Rémusat, in
Lamétherie, 'Jour. de Phys.', 1819, Mai p. 264.)
The largest meteoric masses as yet known are those of Otumpa, in Chaco, and
of Bahia, in Brazil, described by Rubi de Celis as being from 7 to 7 1/2
feet in length. The meteoric stone of gos Potamos, celebrated in antiquity,
and even mentioned in the Chronicle of the Parian Marbles, which fell about
the year in which Socrates was born, has been described as of the size of
two mill-stones, and equal in weight to a full wagon load. Notwithstanding
the failure that has attended the efforts of the African traveler, Brown, I
do not wholly relinquish the hope that, even after the lapse of 2312 years,
this Thracian meteoric mass, which it would be so difficult to destroy, may
be found, since the region in which it fell is now bcome so easy of access
to European travelers. The huge aërolite which in the beginning of the
tenth century fell into the river at Narni, projected between three and four
feet above the surface of the water, as we learn from a document lately
discovered by Pertz. It must be remarked that these meteoric bodies,
whether in ancient or modern times can only be regarded as the principal
fragments of masses that have been broken up by the explosion either of a
fire-ball of a dark cloud.
On considering the enormous velocity with which, as has been mathematically
proved, meteoric stones reach the earth from the extremest confines of the
atmosphere, and the lengthened course traversed by fire-balls through the
denser strata of the air, it seems more than improbable that these
metalliferous stony masses, containing perfectly-formed crystals of olivine,
labradorite, and pyroxene, should in so short a period of time has been
converted from a vaporous condition to a solid nucleus. Moreover, that
which falls from meteoric masses, even where the internal composition is
chemically different, exhibits almost always the peculiar character of a
fragment, being of a prismatic or truncated pyramidal form, with broad,
somewhat curved faces, and rounded angles. But whence comes this form,
which was first recognized by Schreiber as characteristic of the 'severed'
part of a rotating planetary body? Here, as in the sphere of organic life,
all that appertains to the history of development remains hidden in
obscurity. Meteoric masses become luminous and kindle at heights which
p 118
must be regarded as almost devoid of air, of occupied by an atmosphere that
does not even contain 1/100000th part of oxygen. The recent investigations
of Biot on the important phenomenon of twilight* have considerably lowered
the lines which had, perhaps with some degree of temerity, been usually
termed the boundaries of the atmosphere; but processes of light may be
evolved independently of the presence of oxygen, and Poisson conjectured
that aëroliteswere ignited far beyond the range of our atmosphere.
Numerical calculation and geometrical measurement are the only means by
which as in the case of the larger bodies of our solar system, we are
enabled to impart a firm and safe basis to our investigations of meteoric
stones.
[footnote] *Biot, 'Traité d'Astronomie Physique' (3ème éd.), 1841, t.
i., p. 149, 177, 238, 312. My lamented friend Poisson endeavored, in a
singular manner, to solve the difficulty attending an assumption of the
spontaneous ignition of meteoric stones at an elevation where the density of
the atmosphere is almost null. These are his words: "It is difficult to
attribute, as is uaually done, the incandescence of aërolites to friction
against the molecules of the atmosphere at an elevation above the earth
where the density of the air is almost null. May we not suppose that the
electric fluid, in a neutral condition, forms a kind of atmosphere,
extending far beyond the mass of our atmosphere, yet subject to terrestrial
attraction, although physically imponderable, and consequently following our
globe in its motion? According to this hypothesis, the bodies of which we
have been speaking would, on entering this imponderable atmosphere,
decompose the neutral fluid by their unequal action on the two
electricities, and they would thus be heated, and in a state of
incandescence, by becoming electrified." (Poisson, 'Rech. sur la
Probabilité des Jugements', 1837, p. 6.)
Although Halley pronounced the great fire-ball of 1686, whose motion was
opposite to that of the earth in its orbit,* to be a cosmical body, Chadni,
in 1794, first recognized, with ready acuteness of mind, the connection
between fire-balls and the stones projected from the atmosphere, and the
motions of the former bodies in space.**
[footnote] *'Philos. Transact.', vol. xxix., p. 161-163.
[footnote] **The first edition of Chlandni's important treatise, 'Ueber den
Ursprung der von Pallas gefundenen und anderen Eisenmassen' (On the Origin
of the masses of Iron found by Pallas, and other similar masses), appeared
two months prior to the shower of stones at Siena, and two years before
Lichtenberg stated, in the 'Güttingen Taschenbuch', that "stones reach our
atmosphere from the remoter regions of space.' Comp., also, Olbers's letter
to Benzenberg, 18th Nov., 1837, in Benzenberg's 'Treatise on Shooting
Stars', p. 186.
A brilliant confirmation of the cosmical origin of these phenomena has been
afforded by Denison Olmsted, at New Haven, Connecticut, who has shown on the
concurrent authority of all eye-witnesses, that during the celebrated fall
of shooting stars on the night between the 12th
p 119
and 13th of November, 1833, the fire-balls and shooting stars all emerged
from one and the same quarter of the heavens, namely, in the vicinity of the
star 'gamma' in the constellation Leo, and did not deviate from this point,
although the star changed its apparent height and azimuth during the time of
the observation. Such an independence of the Earth's rotation shows that
the luminous body must have reached our atmosphere from 'without.'
According to Encke's computation* of the whole
p 120
number of observations made in the United States of North America, between
the thirty-fifth and the forty-second degrees of latitude, it would appear
that all these meteors came from the same point of space in the direction in
which the Earth was moving at the time.
[footnote] *Encke, in Poggend., 'Annalen', bd. xxxiii. (1834), s. 213.
Arago, in the 'Annuaire' for 1836, p. 291. Two letters which I wrote to
Benzenberg, May 19 and October 22, 1837, on the conjectural precession of
the nodes in the orbit of periodical falls of shooting stars. (Benzenberg's
'Sternsch.', s. 207 and 209.) Olbers subsequently adopted this opinion of
the gradual retardation of the November phenomenon. ('Astron. Nachr.',
1838, No. 372, s. 180.) If I may venture to combine two of the falls of
shooting stars mentioned by the Arabian writers with the epochs found by
Boguslawski for the fourteenth century, I obtain the following more or less
accordant elements of the movements of the nodes:
In Oct., 902, on the night in which King Ibrahim ben Ahmed died, there
fell a heavy shower of shooting stars, "like a fiery rain;" and this year
was, therefore, called the year of stars. (Conde, 'Hist. de la Domin.' de
los Arabes', p. 346.)
On the 19th of Oct., 1202, the stars were in motion all night. "They
fell like locusts." ('Comptes Rendus', 1837, t. i., p. 294; and Fræhn, in
the 'Bull. de l'Académie de St. Pétersbourg', t. iii., p. 308.)
On the 21st Oct., O.S., 1366, "'die sequente post festum XI. millia
Virginum ab hora matutina usque ad horam primam visæ sunt quasi stellæ de
cælo cadere continuo, et in tanta multitudine, quod nemo narrare suf
ficit.'" This remarkable notice, of which we shall speak more fully in the
subsequent part of this work, was found by the younger Von Boguslawski, in
Benesse (de Horowic) de Weitmil or Weithmül, 'Chronicon Ecclesiæ
Pragensis', p. 389. This chronicle may also be found in the second part of
'Scriptores rerum Bohemicarum', by Pelzel and Dobrowsky, 1784. (Schum.,
'Astr. Nachr.', Dec., 1839.)
On the night between the 9th and 10th of November, 1787, many falling
stars were observed at Manheim, Southern Germany, by Hemmer (Kämtz,
'Meteor.', th. iii., s. 237.)
After midnight, on the 12th of November, 1799, occurred the
extraordinary fall of stars at Cumana, which Bonpland and myself have
described, and which was observed over a great part of the earth. ('Relat.
Hist.', t. i., p. 519-527.)
Between the 12th and 13th of November, 1822, shooting stars,
intermingled with fire-balls, were seen in large numbers by Kloden, at
Potsdam. (Gilbert's 'Ann.', bd. lxxii., s. 291.)
On the 13th of November, 1831, at 4 o'clock in the morning, a great
shower of falling stars was seen by Captain Bérard, on the Spanish coast,
near Carthagena del Levante. ('Annuaire', 1836, p. 297.)
In the night between the 12th and 13th of November, 1833, occurred the
phenomenon so admirably described by Professor Olmsted, in North America.
In the night of the 13-14th of November, 1834, a similar fall of
shooting stars was seen in North America, although the numbers were not
quite so considerable. (Poggend., 'Annalen', bd. xxxiv., s. 129.)
On the 13th of November, 1835, a barn was set on fire by the fall of a
sporadic fire-ball, at Belley, in the Department de l'Ain. ('Annuaire',
1836, p. 296.)
In the year 1838, the stream showed itself most decidedly on the night
of the 13-14th of November. ('Astron. Nachr.', 1838, No. 372.)
On the recurrence of falls of shooting stars in North America, in the month
of November of the years 1834 and 1837, and in the analogous falls observed
at Bremen in 1838, a like general parallelism of the orbits, and the same
direction of the meteors from the constellation Leo, were again noticed. It
has been supposed that a greater parallelism was observable in the direction
of periodic falls of shooting stars than in those of sporadic occurrence;
and it has further been remarked, that in the periodically-recurring falls
in the month of August, as, for instance, in the year 1839, the meteors came
principally from one point between Perseus and Taurus, toward the latter of
which constellations in the Earth was then moving. This peculiarity of the
phenomenon, manifested in the retrograde direction of the orbits in November
and August, should be thoroughly investigated by accurate observations, in
order that it may either be fully confirmed or refuted.
The heights of shooting stars, that is to say, the heights of the points at
which they begin and cease to be visible, vary exceedingly, fluctuating
between 16 and 140 miles. This important result, and the enormous velocity
of these problematical asteroids, were first ascertained by Benzenberg and
Brandes, by simultaneous observations and determinations of parallax at the
extremities of a base line of 49,020 feet in length.*
[footnote] *I am well aware that, among the 62 shooting stars
simultaneously observed in Silesia, in 1823, at the suggestion of Professor
Brandes some appeared to have an elevation of 183 to 240, or even 400 miles.
(Brandes, 'Unterhaltungen für Freunde der Astronomie und Physik', heft i.,
s. 48. Instructive Narratives for the Lovers of Astronomy and Physics.)
But Olbers considered that all determinations for elevations beyond 120
miles must be doubtful, owing to the smallness of the parallax.
The relative velocity of motion is from 18 to 36 miles in a second, and
consequently equal to planetary velocity. This planetary velocity,* as well
as the direction of the orbits
p 121
of fire-balls and shooting stars, which has frequently been observed to be
opposite to that of the Earth, may be considered as conclusive arguments
against the hypothesis that aërolites derive their origin from the
so-called active 'lunar volcanoes.'
[footnote] *The planetary velocity of translation, the movement in the
orbit, is in Mercury 26.4, in Venus 19.2, and in the Earth 16.4 miles in a
second.
Numerical views regarding a greater or lesser volcanic force on a small
cosmical body, not surrounded by any atmosphere, must, from their nature, be
wholly arbitrary. We may imagine the reaction of the interior of a planet
on its crust ten or even a hundred times greater than that of our present
terrestrial volcanoes; the direction of masses projected from a satellite
revolving from west to east might appear retrogressive, owing to the Earth
in its orbit subsequently reaching that point of space at which these bodies
fall. If we examine the whole sphere of relations which I have touched upon
in this work, in order to escape the charge of having made unproved
assertions, we shall find that the hypothesis of the selenic origin of
meteoric stones* depends upon a number of conditions
p 122
whose accidental coincidence could alone convert a possible into an actual
fact.