VOLCANIC DISTRICT OF NAPLES--_continued_.
Dimensions and structure of the cone of Vesuvius--Fluidity and
motion of lava--Dikes--Alluviums called "aqueous lavas"--Origin and
composition of the matter enveloping Herculaneum and
Pompeii--Condition and contents of the buried cities--Small number
of skeletons--State of preservation of animal and vegetable
substances--Rolls of papyrus--Stabiae--Torre del Greco--Concluding
remarks on the Campanian volcanoes.
_Structure of the cone of Vesuvius._--Between the end of the eighteenth
century and the year 1822, the great crater of Vesuvius had been
gradually filled by lava boiling up from below, and by scoriae falling
from the explosions of minor mouths which were formed at intervals on
its bottom and sides. In place of a regular cavity, therefore, there was
a rough and rocky plain, covered with blocks of lava and scoriae, and cut
by numerous fissures, from which clouds of vapor were evolved. But this
state of things was totally changed by the eruption of October, 1822,
when violent explosions, during the space of more than twenty days,
broke up and threw out all this accumulated mass, so as to leave an
immense gulf or chasm, of an irregular, but somewhat elliptical shape,
about three miles in circumference when measured along the very sinuous
and irregular line of its extreme margin, but somewhat less than three
quarters of a mile in its longest diameter, which was directed from N.
E. to S. W.[518] The depth of this tremendous abyss has been variously
estimated; for from the hour of its formation it increased daily by the
dilapidation of its sides. It measured, at first, according to the
account of some authors, two thousand feet in depth from the extreme
part of the existing summit;[519] but Mr. Scrope, when he saw it, soon
after the eruption, estimated its depth at less than half that amount.
More than eight hundred feet of the cone was carried away by the
explosions, so that the mountain was reduced in height from about 4200
to 3400 feet.[520]
As we ascend the sloping sides, the volcano appears a mass of loose
materials--a mere heap of rubbish, thrown together without the slightest
order; but on arriving at the brim of the crater, and obtaining a view
of the interior, we are agreeably surprised to discover that the
conformation of the whole displays in every part the most perfect
symmetry and arrangement. The materials are disposed in regular strata,
slightly undulating, appearing, when viewed in front, to be disposed in
horizontal planes. But, as we make the circuit of the edge of the
crater, and observe the cliffs by which it is encircled projecting or
receding in salient or retiring angles, we behold transverse sections of
the currents of lava and beds of sand and scoriae, and recognize their
true dip. We then discover that they incline outwards from the axis of
the cone, at angles varying from 30 degrees. to 40 degrees. The whole
cone, in fact, is composed of a number of concentric coatings of
alternating lavas, sand, and scoriae. Every shower of ashes which has
fallen from above, and every stream of lava descending from the lips of
the crater, have conformed to the outward surface of the hill, so that
one conical envelope may be said to have been successively folded round
another, until the aggregation of the whole mountain was completed. The
marked separation into distinct beds results from the different colors
and degrees of coarseness in the sands, scoriae, and lava, and the
alternation of these with each other. The greatest difficulty, on the
first view, is to conceive how so much regularity can be produced,
notwithstanding the unequal distribution of sand and scoriae, driven by
prevailing winds in particular eruptions, and the small breadth of each
sheet of lava as it first flows out from the crater.
But, on a closer examination, we find that the appearance of extreme
uniformity is delusive; for when a number of beds thin out gradually,
and at different points, the eye does not without difficulty recognize
the termination of any one stratum, but usually supposes it continuous
with some other, which at a short distance may lie precisely in the same
plane. The slight undulations, moreover, produced by inequalities on the
sides of the hill on which the successive layers were moulded, assist
the deception. As countless beds of sand and scoriae constitute the
greater part of the whole mass, these may sometimes mantle continuously
round the whole cone; and even lava streams may be of considerable
breadth when first they overflow, and since, in some eruptions, a
considerable part of the upper portion of the cone breaks down at once,
may form a sheet extending as far as the space which the eye usually
takes in, in a single section.
The high inclination of some of the beds, and the firm union of the
particles even where there is evidently no cement, is another striking
feature in the volcanic tuffs and breccias, which seems at first not
very easy of explanation. But the last great eruption afforded ample
illustration of the manner in which these strata are formed. Fragments
of lava, scoriae, pumice, and sand, when they fall at slight distances
from the summit, are only half cooled down from a state of fusion, and
are afterwards acted upon by the heat from within, and by fumeroles or
small crevices in the cone through which hot vapors are disengaged. Thus
heated, the ejected fragments cohere together strongly; and the whole
mass acquires such consistency in a few days, that fragments cannot be
detached without a smart blow of the hammer. At the same time sand and
scoriae, ejected to a greater distance, remain incoherent.[521]
Sir William Hamilton, in his description of the eruption of 1779, says
that jets of liquid lava, mixed with stones and scoriae, were thrown up
to the height of at least ten thousand feet, having the appearance of a
column of fire.[522] Some of these were directed by the winds towards
Ottajano, and some of them falling almost perpendicularly, still red-hot
and liquid, on Vesuvius, covered its whole cone, part of the mountain of
Somma, and the valley between them. The falling matter being nearly as
vividly inflamed as that which was continually issuing fresh from the
crater, formed with it one complete body of fire, which could not be
less than two miles and a half in breadth, and of the extraordinary
height above mentioned, casting a heat to the distance of at least six
miles round it. Dr. Clarke, also, in his account of the eruption of
1793, says that millions of red-hot stones were shot into the air full
half the height of the cone itself, and then bending, fell all round in
a fine arch. On another occasion he says that, as they fell, they
covered nearly half the cone with fire.
The same author has also described the different appearance of the lava
at its source, and at some distance from it, when it had descended into
the plains below. At the point where it issued, in 1793, from an arched
chasm in the side of the mountain, the vivid torrent rushed with the
velocity of a flood. It was in perfect fusion, unattended with any
scoriae on its surface, or any gross materials not in a state of complete
solution. It flowed with the translucency of honey, "in regular
channels, cut finer than art can imitate, and glowing with all the
splendor of the sun."--"Sir William Hamilton," he continues, "had
conceived that no stones thrown upon a current of lava would make any
impression. I was soon convinced of the contrary. Light bodies, indeed,
of five, ten, and fifteen pounds' weight, made little or no impression
even at the source; but bodies of sixty, seventy, and eighty pounds were
seen to form a kind of bed on the surface of the lava, and float away
with it. A stone of three hundred weight, that had been thrown out by
the crater, lay near the source of the current of lava: I raised it upon
one end, and then let it fall in upon the liquid lava; when it gradually
sunk beneath the surface, and disappeared. If I wished to describe the
manner in which it acted upon the lava, I should say that it was like a
loaf of bread thrown into a bowl of very thick honey, which gradually
involves itself in the heavy liquid, and then slowly sinks to the
bottom.
"The lava, at a small distance from its source, acquires a darker tint
upon its surface, is less easily acted upon, and, as the stream widens,
the surface, having lost its state of perfect solution, grows harder and
harder, and cracks into innumerable fragments of very porous matter, to
which they give the name of scoriae, and the appearance of which has led
many to suppose that it proceeded thus from the mountain. There is,
however, no truth in this. All lava, at its first exit from its native
volcano, flows out in a liquid state, and all equally in fusion. The
appearance of the scoriae is to be attributed only to the action of the
external air, and not to any difference in the materials which compose
it, since any lava whatever, separated from its channel, and exposed to
the action of the external air, immediately cracks, becomes porous, and
alters its form. As we proceeded downwards, this became more and more
evident; and the same lava which at its original source flowed in
perfect solution, undivided, and free from incumbrances of any kind, a
little farther down had its surface loaded with scoriae in such a manner,
that, upon its arrival at the bottom of the mountain, the whole current
resembled nothing so much as a heap of unconnected cinders from an
iron-foundry." In another place he says that "the rivers of lava in the
plain resembled a vast heap of cinders, or the scoriae of an
iron-foundry, rolling slowly along, and falling with a rattling noise
over one another."[523] Von Buch, who was in company with MM. de
Humboldt and Gay-Lussac, describes the lava of 1805 (the most fluid on
record) as shooting suddenly before their eyes from top to bottom of the
cone in one single instant. Professor J. D. Forbes remarks that the
length of the slope of the cone proper being about 1300 feet, this
motion must correspond to a velocity of many hundred feet in a few
seconds, without interpreting Von Buch's expression literally. The same
lava, when it reached the level road at Torre del Greco, moved at the
rate of only eighteen inches per minute, or three-tenths of an inch per
second.[524] "Although common lava," observes Professor Forbes, "is
nearly as liquid as melted iron, when it issues from the orifice of the
crater, its fluidity rapidly diminishes, and as it becomes more and more
burdened by the consolidated slag through which it has to force its way,
its velocity of motion diminishes in an almost inconceivable degree; and
at length, when it ceases to present the slightest external trace of
fluidity, its movement can only be ascertained by careful and repeated
observations, just as in the case of a glacier."[525]
It appears that the intensity of the light and heat of the lava varies
considerably at different periods of the same eruption, as in that of
Vesuvius in 1819 and 1820, when Sir H. Davy remarked different degrees
of vividness in the white heat at the point where the lava
originated.[526]
When the expressions "flame" and "smoke" are used in describing volcanic
appearances, they must generally be understood in a figurative sense. We
are informed, indeed, by M. Abich, that he distinctly saw, in the
eruption of Vesuvius in 1834, the flame of burning hydrogen;[527] but
what is usually mistaken for flame consists of vapor or scoriae, and
impalpable dust illuminated by that vivid light which is emitted from
the crater below, where the lava is said to glow with the splendor of
the sun. The clouds of apparent smoke are formed either of aqueous and
other vapor, or of finely comminuted scoriae.
_Dikes in the recent cone, how formed._--The inclined strata before
mentioned which dip outwards in all directions from the axis of the cone
of Vesuvius, are intersected by veins or dikes of compact lava, for the
most part in a vertical position. In 1828 these were seen to be about
seven in number, some of them not less than four or five hundred feet in
height, and thinning out before they reached the uppermost part of the
cone. Being harder than the beds through which they pass, they have
decomposed less rapidly, and therefore stand out in relief. When I
visited Vesuvius, in November, 1828, I was prevented from descending
into the crater by the constant ejections then thrown out; so that I got
sight of three only of the dikes; but Signor Monticelli had previously
had drawings made of the whole, which he showed me. The dikes which I
saw were on that side of the cone which is encircled by Somma. The
eruption before mentioned, of 1828, began in March, and in the November
following the ejected matter had filled up nearly one-third of the deep
abyss formed at the close of the eruption of 1822. In November I found a
single black cone at the bottom of the crater continually throwing out
scoriae, while on the exterior of the cone I observed the lava of 1822,
which had flowed out six years before, not yet cool, and still evolving
much heat and vapor from crevices.
Hoffmann, in 1832, saw on the north side of Vesuvius, near the peak
called Palo, a great many parallel bands of lava, some from six to eight
feet thick, alternating with scoriae and conglomerate. These beds, he
says, were cut through by many dikes, some of them five feet broad. They
resemble those of Somma, the stone being composed of grains of leucite
and augite.[528]
There can be no doubt that the dikes above mentioned have been produced
by the filling up of open fissures with liquid lava; but of the date of
their formation we know nothing farther than that they are all
subsequent to the year 79, and, relatively speaking, that they are more
modern than all the lavas and scoriae which they intersect. A
considerable number of the upper strata are not traversed by them. That
the earthquakes, which almost invariably precede eruptions, occasion
rents in the mass, is well known; and, in 1822, three months before the
lava flowed out, open fissures, evolving hot vapors, were numerous. It
is clear that such rents must be ejected with melted matter when the
column of lava rises, so that the origin of the dikes is easily
explained, as also the great solidity and crystalline nature of the rock
composing them, which has been formed by lava cooling slowly under great
pressure.
It has been suggested that the frequent rending of volcanic cones during
eruptions may be connected with the gradual and successive upheaval of
the whole mass in such a manner as to increase the inclination of the
beds composing the cone; and in accordance with the hypothesis before
proposed for the origin of Monte Nuovo, Von Buch supposes that the
present cone of Vesuvius was formed in the year 79, not by eruption, but
by upheaval. It was not produced by the repeated superposition of scoriae
and lava cast out or flowing from a central source, but by the uplifting
of strata previously horizontal. The entire cone rose at once, such as
we now see it, from the interior and middle of Somma, and has since
received no accession of height, but, on the contrary, has ever since
been diminishing in elevation.[529]
Although I consider this hypothesis of Von Buch to be quite untenable, I
may mention some facts which may at first sight seem to favor it. These
are recorded by M. Abich in his account of the Vesuvian eruptions of
1833 and 1834, a work illustrated by excellent engravings of the
volcanic phenomena which he witnessed.[530] It appears that, in the year
1834, the great crater of Vesuvius had been filled up nearly to the top
with lava, which had consolidated and formed a level and unbroken plain,
except that a small cone thrown up by the ejection of scoriae rose in the
middle of it like an island in a lake. At length this plain of lava was
broken by a fissure which passed from N. E. to S. W., and along this
line a great number of minute cones emitting vapor were formed. The
first act of formation of these minor cones is said to have consisted of
a partial upheaval of beds of lava previously horizontal, and which had
been rendered flexible by the heat and tension of elastic fluids, which,
rising from below, escaped from the centre of each new monticule. There
would be considerable analogy between this mode of origin and that
ascribed by Von Buch to Vesuvius and Somma, if the dimensions of the
upraised masses were not on so different a scale, and if it was safe to
reason from the inflation of bladders of half-fused lava, from fifteen
to twenty-five feet in height, to mountains attaining an altitude of
several thousand feet, and having their component strata strengthened by
intersecting dikes of solid lava.
At the same time M. Abich mentions, that when, in August, 1834, a great
subsidence took place in the platform of lava within the great crater,
so that the structure of the central cone was laid open, it was seen to
have been evidently formed, _not by upheaval_, but by the fall of
cinders and scoriae which had been thrown out during successive
eruptions.[531]
Previous to the year 79, Vesuvius appears, from the description of its
figure given by Strabo, to have been a truncated cone, having a level
and even outline as seen from a distance. That it had a crater on its
summit, we may infer from a passage in Plutarch, on which Dr. Daubeny
has judiciously commented in his treatise on volcanoes.[532] The walls
of the crater were evidently entire, except on one side, where there was
a single narrow breach. When Spartacus, in the year 72, encamped his
gladiators in this hollow, Clodius, the praetor, besieged him there,
keeping the single outlet carefully guarded, and then let down his
soldiers by scaling-ladders over the steep precipices which surrounded
the crater, at the bottom of which the insurgents were encamped. On the
side towards the sea, the walls of this original cavity, which must have
been three miles in diameter, have been destroyed, and Brieslak was the
first to announce the opinion, that this destruction happened during the
tremendous eruption which occurred in 79, when the new cone, now called
Vesuvius, was thrown up, which stands encircled on three sides by the
ruins of the ancient cone, called Monte Somma.
[Illustration: Fig. 45.
Supposed section of Vesuvius and Somma.
_a_, Monte Somma, or the remains of the ancient cone of Vesuvius.
_b_, The Pedamentina, a terrace-like projection, encircling the base of
the recent cone of Vesuvius on the south side.
_c_, Atrio del Cavallo.[533]
_d_, _e_, Crater left by eruption of 1822.
_f_, Small cone thrown up in 1828, at the bottom of the great crater.
_g_, _g_, Dikes intersecting Somma.
_h_, _h_, Dikes intersecting the recent cone of Vesuvius.]
In the annexed diagram (fig. 45) it will be seen that on the side of
Vesuvius opposite to that where a portion of the ancient cone of Somma
(_a_) still remains, is a projection (_b_) called the Pedamentina, which
some have supposed to be part of the circumference of the ancient crater
broken down towards the sea, and over the edge of which the lavas of the
modern Vesuvius have poured; the axis of the present cone of Vesuvius
being, according to Visconti, precisely equidistant from the escarpment
of Somma and the Pedamentina.
In the same diagram I have represented the slanting beds of the cone of
Vesuvius as becoming horizontal in the Atrio del Cavallo (at _c_), where
the base of the new cone meets the precipitous escarpment of Somma; for
when the lava flows down to this point, as happened in 1822, its
descending course is arrested, and it then runs in another direction
along this small valley, circling round the base of the cone. Sand and
scoriae, also, blown by the winds, collect at the base of the cone, and
are then swept away by torrents; so that there is always here a flatish
plain, as represented. In the same manner, the small interior cone
(_f_) must be composed of sloping beds, terminating in a horizontal
plain; for, while this monticule was gradually gaining height by
successive ejections of lava and scoriae, in 1828, it was always
surrounded by a flat pool of semi-fluid lava, into which scoriae and sand
were thrown.
In the steep simicircular escarpment of Somma, which faces the modern
Vesuvius, we see a great number of sheets of lava inclined at an angle
of about 26 degrees. They alternate with scoriae, and are intersected
by numerous dikes, which, like the sheets of lava, are composed chiefly
of augite, with crystals of leucite, but the rock in the dikes is more
compact, having cooled and consolidated under greater pressure. Some of
the dikes cut through and shift others, so that they have evidently been
formed during successive eruptions. While the higher region of Somma is
made up of these igneous products, there appear on its flanks, for some
depth from the surface, as seen in a ravine called the "Fossa Grande,"
beds of white pumiceous tuff, resembling the tuff which, at Pausilippo,
and other places, near Naples, contain shells of living Mediterranean
species. It is supposed by Pilla, Von Buch, and others, that the
tufaceous beds, which rise in Somma to more than half the height of that
mountain, are, in like manner, of submarine origin, because a few
sea-shells have been found in them, here and there, together with
serpulae of recent species attached to included blocks of
limestone.[534]
It is contended, therefore, that as these strata were once accumulated
beneath the sea, they may have been subjected as they rose to such an
upward movement as may have given rise to a conical hill; and this
hypothesis, it is said, acquires confirmation from the fact, that the
sheets of lava near the summit of Somma are so compact and crystalline,
and of such breadth individually, as would not have been the case had
they run down a steep slope. They must, therefore, have consolidated on
a nearly level surface, and have been subsequently uplifted into their
present inclined position.
Unfortunately there are no sections of sufficient depth and continuity
on the flanks of Somma, to reveal to us clearly the relations of the
lava, scoriae, and associated dikes, forming the highest part of the
mountain, with the marine tuffs observed on its declivity. Both may,
perhaps, have been produced contemporaneously when Somma raised its
head, like Stromboli, above the sea, its sides and base being then
submerged. Such a state of things may be indicated by a fact noticed by
Von Buch, namely, that the pumiceous beds of Naples, when they approach
Somma, contain fragments of the peculiar leucitic lava proper to that
mountain, which are not found in the same tuff at a greater
distance.[535] Portions, therefore, of this lava were either thrown out
by explosions, or torn off by the waves, during the deposition of the
pumiceous strata beneath the sea.
We have as yet but a scanty acquaintance with the laws which regulate
the flow of lava beneath water, or the arrangement of scoriae and
volcanic dust on the sides of a submarine cone. There can, however, be
little doubt that showers of ejected matter may settle on a steep slope,
and may include shells and the remains of aquatic animals, which
flourish in the intervals between eruptions. Lava under the pressure of
water would be less porous; but, as Dr. Daubeny suggests, it may retain
its fluidity longer than in the open air; for the rapidity with which
heated bodies are cooled by being plunged into water arises chiefly from
the conversion of the lower portions of water into steam, which steam
absorbing much heat, immediately ascends, and is reconverted into water.
But under the pressure of a deep ocean, the heat of the lava would be
carried off more slowly, and only by the circulation of ascending and
descending currents of water, those portions nearest the source of heat
becoming specifically light, and consequently displacing the water
above. This kind of circulation would take place with much less rapidity
than in the atmosphere, inasmuch as the expansion of water by equal
increments of heat is less considerable than that of air.[536]
We learn from the valuable observations made by Mr. Dana on the active
volcanoes of the Sandwich Islands, that large sheets of compact basaltic
lava have been poured out of craters at the top or near the summits of
flattened domes higher than Etna, as in the case of Mount Loa for
example, where a copious stream two miles broad and twenty-five miles
long proceeded from an opening 13,000 feet above the level of the sea.
The usual slope of these sheets of lava is between 5 degrees. and 10
degrees.; but Mr. Dana convinced himself that, owing to the suddenness
with which they cool in the air, some lavas may occasionally form on
slopes equalling 25 degrees, and still preserve a considerable
compactness of texture. It is even proved, he says, from what he saw in
the great lateral crater of Kilauea, on the flanks of Mount Loa, that a
mass of such melted rock may consolidate at an inclination of 30
degrees, and be continuous for 300 or 400 feet. Such masses are narrow,
he admits, "but if the source had been more generous, they would have
had a greater breadth, and by a succession of ejections overspreading
each cooled layer, a considerable thickness might have been
attained."[537] The same author has also shown, as before mentioned,
that in the "cinder cones" of the Sandwich Islands, the strata have an
original inclination of between 35 degrees and 40 degrees.[538]
Mr. Scrope, writing in 1827, attributed the formation of a volcanic cone
chiefly to matter ejected from a central orifice, but partly to the
injection of lava into dikes, and "to that force of gaseous expansion,
the intensity of which, in the central parts of the cone, is attested
by local earthquakes, which so often accompany eruptions.[539] It is the
opinion of MM. Von Buch, De Beaumont, and Dufranoy, that the sheets of
lava on Somma are so uniform and compact, that their original
inclination did not exceed four or five degrees, and that four-fifths,
therefore, of their present slope is due to their having been
subsequently tilted and upraised. Notwithstanding the light thrown by M.
de Beaumont on the laws regulating the flow and consolidation of lava, I
do not conceive that these laws are as yet sufficiently determined to
warrant us in assigning so much of the inclined position of the beds of
Somma to the subsequent rending and dislocation of the cone. Even if
this were admitted, it is far more in harmony with the usual mode of
development of volcanic forces to suppose the movement which modified
the shape of the cone to have been intermittent and gradual, and not to
have consisted of a single effort, or one sudden and violent
convulsion.[540]
_Vesuvian lavas._--The lavas of Somma are characterized by containing
disseminated crystals of leucite (called, by the French, amphigene), a
mineral said to be very rare in the modern lavas of Vesuvius, which are
in general much more scoriaceous and less crystalline than those of
Somma.[541]
At the fortress near Torre del Greco a section is exposed, fifteen feet
in height, of a current which ran into the sea; and it evinces,
especially in the lower part, a decided tendency to divide into rude
columns. A still more striking example may be seen to the west of Torre
del Annunziata, near Forte Scassato, where the mass is laid open to the
depth of twenty feet. In both these cases, however, the rock may rather
be said to be divided into numerous perpendicular fissures, than to be
prismatic, although the same picturesque effect is produced. In the
lava-currents of Central France (those of the Vivarais, in particular),
the uppermost portion, often forty feet or more in thickness, is an
amorphous mass passing downwards into lava irregularly prismatic; and
under this there is a foundation of regular and vertical columns; but
these lavas are often one hundred feet or more in thickness. We can
scarcely expect to discover the same phenomenon in the shallow currents
of Vesuvius, where the lowest part has cooled more rapidly, although it
may be looked for in modern streams in Iceland, which exceed even those
of ancient France in volume.
Mr. Scrope mentions that, in the cliffs encircling the modern crater of
Vesuvius, he saw many currents offering a columnar division, and some
almost as regularly prismatic as any ranges of the older basalts; and he
adds, that in some the spheroidal concretionary structure, on a large
scale, was equally conspicuous.[542] Brieslak[543] also informs us that,
in the siliceous lava of 1737, which contains augite, leucite, and
crystals of felspar, he found very regular prisms in a quarry near Torre
del Greco; an observation confirmed by modern authorities.[544]
_Effects of decomposition on lavas._--The decomposition of some of the
felspathic lavas, either by simple weathering, or by gaseous emanations,
converts them from a hard to a soft clayey state, so that they no longer
retain the smallest resemblance to rocks cooled down from a state of
fusion. The exhalations of sulphuretted hydrogen and muriatic acid,
which are disengaged continually from the Solfatara, also produce
curious changes on the trachyte of that nearly extinct volcano: the rock
is bleached, and becomes porous, fissile, and honey-combed, till at
length it crumbles into a white siliceous powder.[545] Numerous globular
concretions, composed of concentric laminae, are also formed by the same
vapors in this decomposed rock.[546]
_Vesuvian minerals._--A great variety of minerals are found in the lavas
of Vesuvius and Somma; augite, leucite, felspar, mica, olivine, and
sulphur are most abundant. It is an extraordinary fact, that in an area
of three square miles round Vesuvius, a greater number of simple
minerals have been found than in any spot of the same dimensions on the
surface of the globe. Hauy enumerated only 380 species of simple
minerals as known to him; and no less than eighty-two had been found on
Vesuvius and in the tuffs on the flanks of Somma before the end of the
year 1828.[547] Many of these are peculiar to that locality. Some
mineralogists have conjectured that the greater part of these were not
of Vesuvian origin, but thrown up in fragments from some older
formation, through which the gaseous explosions burst. But none of the
older rocks in Italy, or elsewhere, contain such an assemblage of
mineral products; and the hypothesis seems to have been prompted by a
disinclination to admit that, in times so recent in the earth's history,
the laboratory of nature could have been so prolific in the creation of
new and rare compounds. Had Vesuvius been a volcano of high antiquity,
formed when nature
Wanton'd as in her prime, and play'd at will
Her virgin fancies,
it would have been readily admitted that these, or a much greater
variety of substances, had been sublimed in the crevices of lava, just
as several new earthy and metallic compounds are known to have been
produced by fumeroles, since the eruption of 1822.
_Mass enveloping Herculaneum and Pompeii._--In addition to the ejections
which fall on the cone, and that much greater mass which finds its way
gradually to the neighboring sea, there is a third portion, often of no
inconsiderable thickness, composed of alluviums, spread over the valleys
and plains at small distances from the volcano. Aqueous vapors are
evolved copiously from volcanic craters during eruptions, and often for
a long time subsequently to the discharge of scoriae and lava: these
vapors are condensed in the cold atmosphere surrounding the high
volcanic peak, and heavy rains are thus caused. The floods thus
occasioned, sweep along the impalpable dust and light scoriae, till a
current of mud is produced, which is called in Campania "lava d' acqua,"
and is often more dreaded than an igneous stream (lava di fuoco), from
the greater velocity with which it moves. So late as the 27th of
October, 1822, one of these alluviums descended the cone of Vesuvius,
and, after overspreading much cultivated soil, flowed suddenly into the
villages of St. Sebastian and Massa, where, filling the streets and
interior of some of the houses, it suffocated seven persons. It will,
therefore, happen very frequently that, towards the base of a volcanic
cone, alternations will be found of lava, alluvium, and showers of
ashes.
To which of these two latter divisions the mass enveloping Herculaneum
and Pompeii should be referred, has been a question of the keenest
controversy; but the discussion might have been shortened, if the
combatants had reflected that, whether volcanic sand and ashes were
conveyed to the towns by running water, or through the air, during an
eruption, the interior of buildings, so long as the roofs remain entire,
together with all underground vaults and cellars, could be filled only
by an alluvium. We learn from history, that a heavy shower of sand,
pumice, and lapilli, sufficiently great to render Pompeii and
Herculaneum uninhabitable, fell for eight successive days and nights in
the year 79, accompanied by violent rains.[548] We ought, therefore, to
find a very close resemblance between the strata covering these towns
and those composing the minor cones of the Phlegraean Fields, accumulated
rapidly, like Monte Nuovo, during a continued shower of ejected matter;
with this difference however, that the strata incumbent on the cities
would be horizontal, whereas those on the cones are highly inclined; and
that large angular fragments of rock, which are thrown out near the
vent, would be wanting at a distance where small lapilli only can be
found. Accordingly, with these exceptions, no identity can be more
perfect than the form, and distribution of the matter at the base of
Monte Nuovo, as laid open by the encroaching sea, and the appearance of
the beds superimposed on Pompeii. That city is covered with numerous
alternations of different horizontal beds of tuff and lapilli, for the
most part thin, and subdivided into very fine layers. I observed the
following section near the amphitheatre, in November, 1828--(descending
series):--
Feet Inches.
1. Black sparkling sand from the eruption of 1822,
containing minute regularly formed crystals of augite
and tourmaline 0 2-1/2
2. Vegetable mould 3 0
3. Brown incoherent tuff, full of _pisolitic globules_
in layers, from half an inch to three inches in
thickness 1 6
4. Small scoriae and white lapilli 0 3
5. Brown earthy tuff, with numerous pisolitic globules 0 9
6. Brown earthy tuff, with lapilli divided into layers 4 0
7. Layer of whitish lapilli 0 1
8. Gray solid tuff 0 3
9. Pumice and white lapilli 0 3
-------
10 3-1/2
-------
Many of the ashes in these beds are vitrified, and harsh to the touch.
Crystals of leucite, both fresh and farinaceous, have been found
intermixed.[549] The depth of the bed of ashes above the houses is
variable, but seldom exceeds twelve or fourteen feet, and it is said
that the higher part of the amphitheatre always projected above the
surface; though if this were the case, it seems inexplicable that the
city should never have been discovered till the year 1750. It will be
observed in the above section that two of the brown, half-consolidated
tuffs are filled with small pisolitic globules. This circumstance is not
alluded to in the animated controversy which the Royal Academy of Naples
maintained with one of their members, Signor Lippi, as to the origin of
the strata incumbent on Pompeii. The mode of aggregation of these
globules has been fully explained by Mr. Scrope, who saw them formed in
great numbers in 1822, by rain falling during the eruption on fine
volcanic sand, and sometimes also produced like hail in the air, by the
mutual attraction of the minutest particles of fine damp sand. Their
occurrence, therefore, agrees remarkably well with the account of heavy
rain, and showers of sand and ashes recorded in history.[550]
Lippi entitled his work, "Fu il fuoco o l' acqua che sottero Pompei ed
Ercolano?"[551] and he contended that neither were the two cities
destroyed in the year 79, nor by a volcanic eruption, but purely by the
agency of water charged with transported matter. His letters, wherein he
endeavored to dispense, as far as possible, with igneous agency, even at
the foot of the volcano, were dedicated, with great propriety, to
Werner, and afford an amusing illustration of the polemic style in which
geological writers of that day indulged themselves. His arguments were
partly of an historical nature, derived from the silence of contemporary
historians, respecting the fate of the cities, which, as we have already
stated, is most remarkable, and partly drawn from physical proofs. He
pointed out with great clearness the resemblance of the tufaceous matter
in the vaults and cellars at Herculaneum and Pompeii to aqueous
alluviums, and its distinctness from ejections which had fallen through
the air. Nothing, he observes, but moist pasty matter could have
received the impression of a woman's breast, which was found in a vault
at Pompeii, or have given the cast of a statue discovered in the
theatre at Herculaneum. It was objected to him, that the heat of the
tuff in Herculaneum and Pompeii was proved by the carbonization of the
timber, corn, papyrus-rolls, and other vegetable substances there
discovered; but Lippi replied with truth, that the papyri would have
been burnt up if they had come in contact with fire, and that their
being only carbonized was a clear demonstration of their having been
enveloped, like fossil wood, in a sediment deposited from water. The
Academicians, in their report on his pamphlet, assert, that when the
amphitheatre was first cleared out, the matter was arranged on the steps
in a succession of concave layers, accommodating themselves to the
interior form of the building, just as snow would lie if it had fallen
there. This observation is highly interesting, and points to the
difference between the stratification of ashes in an open building and
of mud derived from the same in the interior of edifices and cellars.
Nor ought we to call the allegation in question, because it could not be
substantiated at the time of the controversy after the matter had been
all removed; although Lippi took advantage of this removal, and met the
argument of his antagonists by requiring them to prove the fact. There
is decisive evidence that no stream of lava has ever reached Pompeii
since it was first built, although the foundations of the town stand
upon the old leucitic lava of Somma; several streams of which, with tuff
interposed, had been cut through in excavations.
_Infusorial beds covering Pompeii._--A most singular and unexpected
discovery has been recently made (1844-5) by Professor Ehrenberg,
respecting the remote origin of many of the layers of ashes and pumice
enveloping Pompeii. They are, he says, in great part, of organic and
freshwater origin, consisting of the siliceous cases of microscopic
infusoria. What is still more surprising, this fact proves to be by no
means an isolated or solitary example of an intimate relation between
organic life and the results of volcanic activity. On the Rhine, several
beds of tuff and pumiceous conglomerate, resembling the mass incumbent
upon Pompeii and closely connected with extinct volcanoes, are now
ascertained to be made up to a great extent of the siliceous cases of
infusoria (or Diatomaceae), invisible to the naked eye, and often half
fused.[552] No less than 94 distinct species have already been detected
in one mass of this kind, more than 150 feet thick, at Hochsimmer, on
the left bank of the Rhine, near the Laacher-see. Some of these Rhenish
infusorial accumulations appear to have fallen in showers, others to
have been poured out of lake-craters in the form of mud, as in the Brohl
valley.
In Mexico, Peru, the Isle of France, and several other volcanic regions,
analogous phenomena have been observed, and everywhere the species of
infusoria belong to freshwater and terrestrial genera, except in the
case of the Patagonian pumiceous tuffs, specimens of which, brought
home by Mr. Darwin, are found to contain the remains of marine
animalcules. In various kinds of pumice ejected by volcanoes, the
microscope has revealed to Professor Ehrenberg the siliceous cases of
infusoria often half obliterated by the action of heat, and the fine
dust thrown out into the air during eruptions, is sometimes referable to
these most minute organic substances, brought up from considerable
depths, and sometimes mingled with small particles of vegetable matter.
In what manner did the solid coverings of these most minute plants and
animalcules, which can only originate and increase at the surface of the
earth, sink down and penetrate into subterranean cavities, so as to be
ejected from the volcanic orifices? We have of late years become
familiar with the fact, in the process of boring Artesian wells, that
the seeds of plants, the remains of insects, and even small fish, with
other organic bodies, are carried in an uninjured state by the
underground circulation of waters, to the depth of many hundred feet.
With still greater facility in a volcanic region we may conjecture, that
water and mud full of invisible infusoria may be sucked down, from time
to time, into subterranean rents and hollows in cavernous lava which has
been permeated by gases, or in rocks dislocated by earthquakes. It often
happens that a lake which has endured for centuries in a volcanic
crater, disappears suddenly on the approach of a new eruption. Violent
shocks agitate the surrounding region, and ponds, rivers, and wells are
dried up. Large cavities far below may thus become filled with fen-mud
chiefly composed of the more indestructible and siliceous portions of
infusoria, destined perhaps to be one day ejected in a fragmentary or
half-fused state, yet without the obliteration of all traces of organic
structure.[553]
_Herculaneum._--It was remarked that no lava has flowed over the site of
Pompeii, since that city was built, but with Herculaneum the case is
different. Although the substance which fills the interior of the houses
and the vaults must have been introduced in a state of mud, like that
found in similar situations in Pompeii; yet the superincumbent mass
differs wholly in composition and thickness. Herculaneum was situated
several miles nearer to the volcano, and has, therefore, been always
more exposed to be covered, not only by showers of ashes, but by
alluviums and streams of lava. Accordingly, masses of both have
accumulated on each other above the city, to a depth of nowhere less
than 70, and in many places of 112 feet.[554]
The tuff which envelops the buildings consists of comminuted volcanic
ashes, mixed with pumice. A mask imbedded in this matrix has left a
cast, the sharpness of which was compared by Hamilton to those in
plaster of Paris; nor was the mask in the least degree scorched, as if
it had been imbedded in heated matter. This tuff is porous; and, when
first excavated, is soft and easily worked, but acquires a considerable
degree of induration on exposure to the air. Above this lowest stratum
is placed, according to Hamilton, "the matter of six eruptions," each
separated from the other by veins of good soil. In these soils Lippi
states that he collected a considerable number of land shells--an
observation which is no doubt correct; for many snails burrow in soft
soils, and some Italian species descend, when they hybernate, to the
depth of five feet and more from the surface. Della Torre also informs
us that there is in one part of this superimposed mass a bed of true
siliceous lava (_lava di pietra dura_); and, as no such current is
believed to have flowed till near one thousand years after the
destruction of Herculaneum, we must conclude, that the origin of a large
part of the covering of Herculaneum was long subsequent to the first
inhumation of the place. That city, as well as Pompeii, was a seaport.
Herculaneum is still very near the shore, but a tract of land, a mile in
length, intervenes between the borders of the Bay of Naples and Pompeii.
In both cases the gain of land is due to the filling up of the bed of
the sea with volcanic matter, and not to elevation by earthquakes, for
there has been no change in the relative level of land and sea. Pompeii
stood on a slight eminence composed of the lavas of the ancient
Vesuvius, and flights of steps led down to the water's edge. The
lowermost of these steps are said to be still on an exact level with the
sea.
_Condition and contents of the buried cities._--After these observations
on the nature of the strata enveloping and surrounding the cities, we
may proceed to consider their internal condition and contents, so far at
least as they offer facts of geological interest. Notwithstanding the
much greater depth at which Herculaneum was buried, it was discovered
before Pompeii, by the accidental circumstance of a well being sunk, in
1713, which came right down upon the theatre, where the statues of
Hercules and Cleopatra were soon found. Whether this city or Pompeii,
both of them founded by Greek colonies, was the more considerable, is
not yet determined; but both are mentioned by ancient authors as among
the seven most flourishing cities in Campania. The walls of Pompeii were
three miles in circumference; but we have, as yet, no certain knowledge
of the dimensions of Herculaneum. In the latter place the theatre alone
is open for inspection; the Forum, Temple of Jupiter, and other
buildings, having been filled up with rubbish as the workmen proceeded,
owing to the difficulty of removing it from so great a depth below
ground. Even the theatre is only seen by torch-light, and the most
interesting information, perhaps, which the geologist obtains there, is
the continual formation of stalactite in the galleries cut through the
tuff; for there is a constant percolation of water charged with
carbonate of lime mixed with a small portion of magnesia. Such mineral
waters must, in the course of time, create great changes in many rocks;
especially in lavas, the pores of which they may fill with calcareous
spar, so as to convert them into amygdaloids. Some geologists,
therefore, are unreasonable when they expect that volcanic rocks of
remote eras should accord precisely with those of modern date; since it
is obvious that many of those produced in our own time will not long
retain the same aspect and internal composition.
Both at Herculaneum and Pompeii, temples have been found with
inscriptions commemorating the rebuilding of the edifices after they had
been thrown down by an earthquake.[555] This earthquake happened in the
reign of Nero, sixteen years before the cities were overwhelmed. In
Pompeii, one-fourth of which is now laid open to the day, both the
public and private buildings bear testimony to the catastrophe. The
walls are rent, and in many places traversed by fissures still open.
Columns are lying on the ground only half hewn from huge blocks of
travertin, and the temple for which they were designed is seen half
repaired. In some few places the pavement had sunk in, but in general it
was undisturbed, consisting of large irregular flags of lava joined
neatly together, in which the carriage wheels have often worn ruts an
inch and a half deep. In the wider streets, the ruts are numerous and
irregular; in the narrower, there are only two, one on each side, which
are very conspicuous. It is impossible not to look with some interest
even on these ruts, which were worn by chariot wheels more than
seventeen centuries ago; and, independently of their antiquity, it is
remarkable to see such deep incisions so continuous in a stone of great
hardness.
_Small number of skeletons._--A very small number of skeletons have been
discovered in either city; and it is clear that most of the inhabitants
not only found time to escape, but also to carry with them the principal
part of their valuable effects. In the barracks at Pompeii were the
skeletons of two soldiers chained to the stocks, and in the vaults of a
country-house in the suburbs were the skeletons of seventeen persons,
who appear to have fled there to escape from the shower of ashes. They
were found inclosed in an indurated tuff, and in this matrix was
preserved a perfect cast of a woman, perhaps the mistress of the house,
with an infant in her arms. Although her form was imprinted on the rock,
nothing but the bones remained. To these a chain of gold was suspended,
and on the fingers of the skeletons were rings with jewels. Against the
sides of the same vault was ranged a long line of earthen amphorae.
The writings scribbled by the soldiers on the walls of their barracks,
and the names of the owners of each house written over the doors, are
still perfectly legible. The colors of fresco paintings on the stuccoed
walls in the interior of buildings are almost as vivid as if they were
just finished. There are public fountains decorated with shells laid out
in patterns in the same fashion as those now seen in the town of Naples;
and in the room of a painter, who was perhaps a naturalist, a large
collection of shells was found, comprising a great variety of
Mediterranean species, in as good a state of preservation as if they had
remained for the same number of years in a museum. A comparison of these
remains, with those found so generally in a fossil state would not
assist us in obtaining the least insight into the time required to
produce a certain degree of decomposition or mineralization; for,
although under favorable circumstances much greater alteration might
doubtless have been brought about in a shorter period, yet the example
before us shows that an inhumation of seventeen centuries may sometimes
effect nothing towards the reduction of shells to the state in which
fossils are usually found.
The wooden beams in the houses at Herculaneum are black on the exterior,
but, when cleft open, they appear to be almost in the state of ordinary
wood, and the progress made by the whole mass towards the state of
lignite is scarcely appreciable. Some animal and vegetable substances of
more perishable kinds have of course suffered much change and decay, yet
the state of preservation of these is truly remarkable. Fishing-nets are
very abundant in both cities, often quite entire; and their number at
Pompeii is the more interesting from the sea being now, as we stated, a
mile distant. Linen has been found at Herculaneum, with the texture well
defined; and in a fruiterer's shop in that city were discovered vessels
full of almonds, chestnuts, walnuts, and fruit of the "carubiere," all
distinctly recognizable from their shape. A loaf, also, still retaining
its form, was found in a baker's shop, with his name stamped upon it. On
the counter of an apothecary was a box of pills converted into a fine
earthy substance; and by the side of it a small cylindrical roll
evidently prepared to be cut into pills. By the side of these was a jar
containing medicinal herbs. In 1827, moist olives were found in a square
glass-case, and "caviare," or roe of a fish, in a state of wonderful
preservation. An examination of these curious condiments has been
published by Covelli of Naples, and they are preserved hermetically
sealed in the museum there.[556]
_Papyri._--There is a marked difference in the condition and appearance
of the animal and vegetable substances found at Pompeii and Herculaneum;
those of Pompeii being penetrated by a gray pulverulent tuff, those in
Herculaneum seeming to have been first enveloped by a paste which
consolidated round them, and then allowed them to become slowly
carbonized. Some of the rolls of papyrus at Pompeii still retain their
form; but the writing, and indeed almost all the vegetable matter,
appear to have vanished, and to have been replaced by volcanic tuff
somewhat pulverulent. At Herculaneum the earthy matter has scarcely ever
penetrated; and the vegetable substance of the papyrus has become a thin
friable black matter, almost resembling in appearance the tinder which
remains when stiff paper has been burnt, in which the letters may still
be sometimes traced. The small bundles of papyri, composed of five or
six rolls tied up together, had sometimes lain horizontally, and were
pressed in that direction, but sometimes they had been placed in a
vertical position. Small tickets were attached to each bundle, on which
the title of the work was inscribed. In one case only have the sheets
been found with writing on both sides of the pages. So numerous are the
obliterations and corrections, that many must have been original
manuscripts. The variety of handwritings is quite extraordinary: nearly
all are written in Greek, but there are a few in Latin. They were almost
all found in a suburban villa in the library of one private individual;
and the titles of four hundred of those least injured, which have been
read, are found to be unimportant works, but all entirely new, chiefly
relating to music, rhetoric, and cookery. There are two volumes of
Epicurus "On Nature," and the others are mostly by writers of the same
school, only one fragment having been discovered, by an opponent of the
Epicurean system, Chrysippus.[557]
_Probability of future discoveries of MSS._--In the opinion of some
antiquaries, not one-hundredth part of the city has yet been explored:
and the quarters hitherto cleared out at a great expense, are those
where there was the least probability of discovering manuscripts. As
Italy could already boast her splendid Roman amphitheatres and Greek
temples, it was a matter of secondary interest to add to their number
those in the dark and dripping galleries of Herculaneum; and having so
many of the masterpieces of ancient art, we could have dispensed with
the inferior busts and statues which could alone have been expected to
reward our researches in the ruins of a provincial town. But from the
moment that it was ascertained that rolls of papyrus preserved in this
city could still be deciphered, every exertion ought to have been
steadily and exclusively directed towards the discovery of other
libraries. Private dwellings should have been searched, before so much
labor and expense were consumed in examining public edifices. A small
portion of that zeal and enlightened spirit which prompted the late
French and Tuscan expedition to Egypt might long ere this, in a country
nearer home, have snatched from oblivion some of the lost works of the
Augustan age, or of eminent Greek historians and philosophers. A single
roll of papyrus might have disclosed more matter of intense interest
than all that was ever written in hieroglyphics.
_Stabiae._--Besides the cities already mentioned, Stabiae, a small town
about six miles from Vesuvius, and near the site of the modern
Castel-a-Mare (see map of volcanic district of Naples), was overwhelmed
during the eruption of 79. Pliny mentions that, when his uncle was
there, he was obliged to make his escape, so great was the quantity of
falling stones and ashes. In the ruins of this place, a few skeletons
have been found buried in volcanic ejections, together with some
antiquities of no great value, and rolls of papyrus, which, like those
of Pompeii, were illegible.
_Torre del Greco overflowed by lava._--Of the towns hitherto mentioned,
Herculaneum alone has been overflowed by a stream of melted matter; but
this did not, as we have seen, enter or injure the buildings, which were
previously enveloped or covered over with tuff. But burning torrents
have often taken their course through the streets of Torre del Greco,
and consumed or inclosed a large portion of the town in solid rock. It
seems probable that the destruction of three thousand of its inhabitants
in 1631, which some accounts attribute to boiling water, was principally
due to one of those alluvial floods which we before mentioned: but, in
1737, the lava itself flowed through the eastern side of the town, and
afterwards reached the sea; and, in 1794, another current, rolling over
the western side, filled the streets and houses, and killed more than
four hundred persons. The main street is now quarried through this lava,
which supplied building stones for new houses erected where others had
been annihilated. The church was half buried in a rocky mass, but the
upper portion served as the foundation of a new edifice.
The number of the population at present is estimated at fifteen
thousand; and a satisfactory answer may readily be returned to those who
inquire how the inhabitants can be so "inattentive to the voice of time
and the warnings of nature,"[558] as to rebuild their dwellings on a
spot so often devastated. No neighboring site unoccupied by a town, or
which would not be equally insecure, combines the same advantages of
proximity to the capital, to the sea, and to the rich lands on the
flanks of Vesuvius. If the present population were exiled, they would
immediately be replaced by another, for the same reason that the Maremma
of Tuscany and the Campagna di Roma will never be depopulated, although
the malaria fever commits more havoc in a few years than the Vesuvian
lavas in as many centuries. The district around Naples supplies one
amongst innumerable examples, that those regions where the surface is
most frequently renewed, and where the renovation is accompanied, at
different intervals of time, by partial destruction of animal and
vegetable life, may nevertheless be amongst the most habitable and
delightful on our globe.
I have already made a similar remark when speaking of tracts where
aqueous causes are now most active; and the observation applies as well
to parts of the surface which are the abode of aquatic animals, as to
those which support terrestrial species. The sloping sides of Vesuvius
give nourishment to a vigorous and healthy population of about eighty
thousand souls; and the surrounding hills and plains, together with
several of the adjoining isles, owe the fertility of their soil to
matter ejected by prior eruptions. Had the fundamental limestone of the
Apennines remained uncovered throughout the whole area, the country
could not have sustained a twentieth part of its present inhabitants.
This will be apparent to every geologist who has marked the change in
the agricultural character of the soil the moment he has passed the
utmost boundary of the volcanic ejections, as when, for example, at the
distance of about seven miles from Vesuvius, he leaves the plain and
ascends the declivity of the Sorrentine Hills.
Yet, favored as this region has been by Nature from time immemorial, the
signs of the changes imprinted on it during the period that it has
served as the habitation of man may appear in after-ages to indicate a
series of unparalleled disasters. Let us suppose that at some future
time the Mediterranean should form a gulf of the great ocean, and that
the waves and tidal current should encroach on the shores of Campania,
as it now advances upon the eastern coast of England; the geologist will
then behold the towns already buried, and many more which will evidently
be entombed hereafter, laid open in the steep cliffs, where he will
discover buildings superimposed above each other, with thick intervening
strata of tuff or lava--some unscathed by fire, like those of
Herculaneum and Pompeii; others half melted down, as in Torre del Greco;
and many shattered and thrown about in strange confusion, as in
Tripergola, beneath Monte Nuovo. Among the ruins will be seen skeletons
of men, and impressions of the human form stamped in solid rocks of
tuff. Nor will the signs of earthquakes be wanting. The pavement of part
of the Domitian Way, and the temple of the Nymphs, submerged at high
tide, will be uncovered at low water, the columns remaining erect and
uninjured. Other temples which had once sunk down, like that of Serapis,
will be found to have been upraised again by subsequent movements. If
they who study these phenomena, and speculate on their causes, assume
that there were periods when the laws of Nature or the whole course of
natural events differed greatly from those observed in their own time,
they will scarcely hesitate to refer the wonderful monuments in question
to those primeval ages. When they consider the numerous proofs of
reiterated catastrophes to which the region was subject, they may,
perhaps, commiserate the unhappy fate of beings condemned to inhabit a
planet during its nascent and chaotic state, and feel grateful that
their favored race has escaped such scenes of anarchy and misrule.
Yet what was the real condition of Campania during those years of dire
convulsion? "A climate where heaven's breath smells sweet and
wooingly--a vigorous and luxuriant nature unparalleled in its
productions--a coast which was once the fairy-land of poets, and the
favorite retreat of great men. Even the tyrants of the creation loved
this alluring region, spared it, adorned it, lived in it, died in
it."[559] The inhabitants, indeed, have enjoyed no immunity from the
calamities which are the lot of mankind; but the principal evils which
they have suffered must be attributed to moral, not to physical,
causes--to disastrous events over which man might have exercised a
control, rather than to the inevitable catastrophes which result from
subterranean agency. When Spartacus encamped his army of ten thousand
gladiators in the old extinct crater of Vesuvius, the volcano was more
justly a subject of terror to Campania, than it has ever been since the
rekindling of its fires.