John Wesley.

A survey of the wisdom of God in the creation; or, A compendium of natural philosophy .. (Volume 3) online

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stones were cast out. The height of the chief hill raised
thereby was about two hundred spans; and its cir-
cumference about two hundred paces. The motion of
the lava in front was very slow ; it gained ground only
on the sides. The hill, where the last aperture was,
burst, and fire issued from all the fissures.

On the 29th, the lava having ceased, appeared to have
reached about a mile in breadth and four miles in length.
The new-raised hills were now quiet ; but the top of
Vesuvius still cast out ashes and smoke, and some show-
ers of stones. About eight at night the new hill was
overturned with a great crack, and on the 30th emitted
nothing. But from the mouth of Vesuvius clouds and
ashes came in great abundance. From the whole it ap-
pears, that the inflammatory contents take fire at a great
deptlj in the cavern, and it is highly probable, it is the
sea-Mater which feeds this subterraneous fire, by means
of some communications which the volcano has with the

Although the fiery eruptions of Mount Vesuvius strike
the neighbourhood with horror; yet as even noxious


things bring some advantage with them, so this moun-
tain, by the sulphureous and nitrous particles with which
k manures the ground, and the heat of its subterrane-
ous passages, much, contributes to its common fertility.
And wherever these inflammable substances abound, it
is better they should have a vent than not. So experi-
ence shews, that this country has had fewer earthquakes,
and those less fatal in their effects, since the eruption of
the subterraneous matter, through the mouth of Vesuvi-
us. And the inhabitants are not much alarmed, at see-
ing the usual vernal explosions.

The distance from Naples to the foot of Vesuvius, is
five Italian miles, from whence to the top is near three
miles further. It properly consists of two hills, though
only one of them emits fire and smoke. The valley be-
tween them is about a mile long, and extremely fertile.
The burning summit, which is the lowest of the two,
is eleven hundred fathoms above the surface of the sea.
From Resina, the ascent grows steeper, and many stones
are scattered about, as memorials of its former devasta-
tions. It is astonishing to think of the force, by which
such huge bulks or four or five hundred weight have
been thrown several miles from the hill.

This being steep, and covered with black ashes, the
ascent is very difficult. From the mouth frequently is-
sues a flood of lava, or composition of sulphur, metals,
and minerals. This ejected matter lies still, one layer
above another, with large stones projecting above the sur-
face, which in their course along the tiery river, were stop*
ped by their inequalities, and hxingin the melted matter,
gradually hardened. These streams are not thrown up
from the mountain, like the stones, but pour down as
from an inclined vessel, proceeding, it seems, from
the whole cavity, which is then full of melted sub-

About half way up the mountain (says Mr. Keysber)
we met with stones of above a hundred weight, glowing
hot, which when broken had exactly the appearance of
red hot iron. As we went on, we heard a most horrid


noise, resembling the discharge of a whole battery of
cannon, and under our feet we perceived a rumbling,
like the boiling of a large caldron. At last we reached
the place where the largest volcano was formerly situ-
ated. But it is now not only choaked up, but covered
with a round pile of ashes and lava. Thirty years since
there was a plain of about three thousand \ards to cross,
before you came to the skirts of this new mountain.
But it is now so enlarged, that in most places, the plain
is but 'about thirty yards broad. Probably in a few
years it will be quite filied up, and the two mountains
joined in one. Here the increase of heat was very sen-
sible, especially at every explosion, when the ashes flew
so strongly in our faces, that we were obliged to cover
our eyes. The ground also was so hot under our feet,
that it burnt the soles of our shoes. Every eruption
was attended with a whizzing noise, like that of maiay
rockets thrown up at once. The clouds of smoke, and
the multitude of stones thrown into the air, totally ob-
scured the sky. Most of the stones, (especially if large)
fell again into the abyss from which they were pro-
jected. Great quantities however fell on the sides of
the mountain, and rolled down with a hideous noise.

Even when all is still, the bottom of the cavity is sel-
dom seen, by reason of the smoke. When it is, it is
subject to great variation. Sometimes it is of a prodi-
gious depth ; at other times hardly more than a hun-
dred feet, according to the rising or falling of the melted
matter, since the last eruption, by the hardening f
which, this bottom is formed.

Since the birth of Christ, there are recorded upwards
of twenty memorable eruptions of Vesuvius. One of
the most violent, was that which happened in the reign
of Titus Vespasian, and destroyed the cities Herculane-
um, Stabice, and Pompeii, which then stood near Na-
ples. During that eruption the ashes were driven as
far as Africa, Syria, and Egypt, and even at Rome, the
sun was darkened by them. These cities were partly
swallowed up, partly buried in the burning lava, so that
not the least remains of them were to be seen.


But within a few years many things hare been dug
out of Herculaneum, near Portici, the king of Naples'
palace. Among these are many paintings done in stucco,
in water colours in fresco. They have been taken from
the walls of an amphitheatre, a temple, and several
houses, and are in great variety, some perfectly well pre-

^Four capifal pieces are so extremely well executed,
that Don Francesco de la Vega, a painter, whom the
king of Naples sent for from Rome, to take draughts of
these paintings, said, " If Raphael were alive, he would
be glad to study these drawings, and perhaps take les*
sons from them." Nothing can be more just and cor-
rect. The muscles are exactly and softly drawn, every
one in its own place, without any of that preternatural
swelling seen in the \voiks of some of the best Italian
masters. And it is surprising to see how fresh the co-
lours are, considering they have been under the ground
above sixteen hundred and fifty years.

The matter thrown out of Vesuvius, shews whence its
fiery eruptions ,arise. For, pour water on sulphur,
mixed with filings of iron, and it soon breaks ou 1 into a
flame. That abundance of sulphur and iron is con-
tained in Vesuvius, appears not only from is ejected, hut
also from the mineral water, issuing from the foot of the
mountain. The neighbouring sea both supplies moist-
ure to these inflammable substances, and also salt and
bitumen. That Vesuvius has a communication with the
sea, experience shews, the waters being surprisingly ab
sorbed, in 1081, before the eruption, so that several ves-
sels before afloat, were left dry. Likewise in 16*98, the
sea suddenly ebbed twelve paces and the mountain dis-
charged a torrent of bituminous matter. When the
discharge ceased, and the sea returned to its former
height, great quantities of shells, half burnt, and. emit-
-ting a sulphurous smell, were found along the shore. la
another violent eruption, not only shells, but sea weeds,
and hot sea water were ejected.

This volcano, however, affords several fresh springs,
some of which are conveyed to Naples, by a beautiful


aqueduct. These waters have not the least heat in them.
Nay, a cold wind is felt to blow, from several fissures
and chasms of the mountain.

The whole country, for twenty miles or more round
Naples, is the product of subterraneous fires. Proba-
bly the sea reached the mountains that lie behind Capua
and Caserta. These fires seem to have worked under
the bottom of the sea, as moles in a field, throwing up
here and there a hilloc. And the matter thrown out of
some of these hillocs formed into settled volcanos, fill-
ing up the space between them, lias composed this part
of the continent, and many of the islands adjoining.

Were the matter carefully examined, it would be
found (just contrary to the common opinion) that most
mountains which are or have been volcanos, owe their
existence to subterraneous fires.

It cannot be denied that Herculaneum and Pompeii
once stood above the ground, though now the latter is
buried ten or twelve feet deep ; the former hi no part
less than seventy, in some parts a hundred and twelve.
As these were buried by an eruption of Vesuvius, A. D*
79, it must be allowed, that whatever matter lies fee*
tween them and -the surface of the earth over tftem,
must have been produced skice this time,

Pompeii being farther off, felt the effects of a single
eruption only. It is covered with white pumice stones,
mixed with fragments of lava and burnt mattei. Over
this there is a stratum of good mould, about two feet
thick. The shower of pumice stones covered also the
town of Stabiae, with a tract of country thirty miles in
circumference. It is observable, the pavement of the
streets of Pompeii is of lava: nay, under the foundation
of the town, "there is a deep stratum of lava and burnt
matter: hence it is clear, there have been eruptions be-
fore that, of 79, the first which is rec6rded in history*

The matter which covers Herculaneum, is not the pro-
duce of one eruption only. From the strata of mould
intermixed it appears, that five or six eruptions have


taken their course over that which lies immediately above
the town, with which the theatre, and most of the houses
are filled. This is not vitrified lava, but a sort of soft
stone, composed of pumice, ashes, and burnt matter.
It is of the same nature with what the Italians call
Tufa, and is in general use for building, and is met with
only in those countries that have been subject to sub-
terraneous fires. As water frequently attends eruptions
of fire, doubtless the first matter that issued from Vesu-
vius, and covered Herculaneum, was in the state of li-
quid mud.

Braccini descended into the crater (or hollow on the
top) of Vesuvius, a little before the eruption in 1631.
He observes, it was then five miles in circumference, and
about 1000 paces deep. Its sides were covered with
brush wood, and at the bottom there was a plain on
which cattle grazed. In the midst of this plain was a
narrow passage, through which by a winding path he de-
scended among rocks and stones into a more spacious
plain, covered with ashes. In this were three little
pools, one of hot water, bitter and corrosive beyond
measure ; another of water salter than that of the sea ;
the third hot, but tasteless.

The great increase of the cone of Vesuvius, from
that time to this, naturally induces one to think, that
the whole cone was raised in like manner, as was also
that part of it now called Soinma. It seems, that this
was what the ancients termed Vesuvius, and that the
conical mountain, at present called by that name, has
been raised by the succeeding eruptions.

From repeated observations, it appears, that all the
soil in the neighbourhood of Vesuvius, is composed
of different strata of erupted matter, to a great depth
below the level of the sea. And undoubtedly this vol-
cano took its rise from the bottom of the sea. The
soil from Capreae to Naples is of the same sort. And
that on which Naples stands, has been evidently pro-
duced by explosions, some of them on the very spot
whereon the city is built. All the high grounds round


it, with the islands of Prochyta and IscJiia, appear like-
wise to have been raised in the same manner.

Such wonderful operations of nature, are certainty
intended for some great purpose. They are not con-
fined to one country ; volcanos exist iu the four quarters
of the globe. We see the fertility of the soil ossasioned
thereby, in what was Thence called Compania felix.
The same is evident in Sicily, justly esteemed one of ihe
most fertile spots in the world. May not subterrane-
ous fire be considered as the great plough (if we may
be allowed the expression) which nature makes use of to
turn up the bowels of the earth, and afford us fie&ii
fields to work upon, when the former are exhausted ?
Perhaps likewise many precious minerals might have re-
mained unknown to us, had it not been for these opera-
tions of nature.

There is great reason to believe that the whole island
of Madeira was at some remote period thrown up by
the explosion of subterraneous fire, as every stone, whe-
ther whole or in fragments, that is seen upon it appears
to have been burnt ; and even the sand itself to be
nothing more than ashes. And it is certain, that part of
the country near the sea is a very exact specimen of the

7- Near Puzzuolo lies Monte Secco, which is Vesuvius
in miniature. Its summit, formerly a cone, is now sunk
into a concave oval, whose shortest diameter is about
one thousand feet, the longest one thousand two hun-
dred and forty-six. It is generally known by the name
of Sollafara. Though Vesuvius is twelve miles distant,
yet they have ^communication with each other. Hence
the subterraneous lire is quiet atSolfatara, when it has a
vent at Vesuvius: whereas the heat at the former in-
creases, when the latter is at rest.

On this mountain are many cracks emitting smoke $
the heat issuing from them is sometimes insupportable.
Hold a piece of iron over, one of these cracks, and a

VOL. IT I, J 1


sweetish fluid will drop from it : but a piece of paper,
instead of being moistened, grows quite dry and stiff.
The stones near these cracks are in continual motion ;
^nd small stones dropped into them are ejected to the
height of twelve feet, like the ponderous masses from
Vesuvius. In some places the sand, by the force of
the vapours, springs up and down, like the sparkling of

Out of Solfatara they extract, beside sulphur, blue vi-
triol, and the best kind of allum. The large leaden
kettles used therein, are not heated by a culinary fire,
but by the natural heat, issuing through holes in the
ground, over which the vessels are placed.

8. Not far from Puzzuolo is Monte Nuovo, which
rose suddenly in the night, between the igth and 20th
of September, 1636. During a dreadful earthquake,
that laid the whole neighbourhood in ruins, the subter-
raneous fire, opening a large chasm in the ground, threw
out such quantities of stones, ashes, bitumen, and sand,
as in twenty-four hours formed this mountain. Its per-
pendicular height is 400 rods, its circuit three miles.
The edge of the first aperture is still visible, a mile in

.circuit, though it is now entirely filled up,

9. An event similar to this occurred more lately.
After a shock of the earth, there was seen from Santo-
rini (an island in the Archipelago, on the coast of Nato-
lia) on the 23d of May, 1/O7, as it were a floating rock.
Some were so bold as to go down upon it, even while
it was rising under their feet. The earth of it was very
light, and contained a small quantity of potters clay. It
increased daily, till it was half a mile in circumference,
and twenty or twenty-five feet high. At this time a
great ridge of rocks, dark and black, rose out of the sea,
and joined to the new island. Then there issued out of
it a thick smoke, with a noise like constant thundering,
(T a discharge of many cannon at once. The sea water
( o itinually bubbled up; and in a short time the new land
presented nothing to view for whole nights, but a great 4


number of stoves, which cast forth flames, with showers
of ashes, and innumerable small stones, red hot. Rocks

vere also darted out of these burning, furnaces, which
mounted up like bombs. This continued till Novem-


There is likewise an island among the Azores, which
rad the same original. On the night between the 7th

and 8th of December, 1720, there was felt a shock
f an earthquake at Tercera : and presently after an

sland rose, from the midst of boiling hot water. It

was nearly round, and high enough to be seen seven or
ight leagues off. But after a little while it sunk, till it

jecame level with the water.

10. On June 4th, 16*93, the mountain on the island
\>rca, in the East-Indies, began about day break, to cast
ut more fire than usual, which continued five or si\
ays, till at last it poured forth, not only a prodigious
ame, but likewise such a black and sulphureous vapour,
lat the inhabitants of Hislo (a village in the western
art of the island, and nearest to the opening) were
'holly covered by it. Quickly followed a stream of
urning brimstone, which consumed many that could
ot escape. Afterwards the inhabitants perceive j, a
reat part of the mountain was sunk down. Anotliei
art sunk three or four days after, and so from time to
me, till the burning lake covered near half the island,
therefore they went on board their boats : from whence
ley perceived huge pieces of the mountain fall into t/ie
ery lake, with a prodigious noise, as if a whole battery of
annon was discharged. The inhabitants of another town
n the east side of the island, not thinking themselves

so great danger, remained a month longer. But the
ery lake approaching nearer and nearer, so that there
as no doubt but it would swallow up the whole island,
icy too fled for their lives, and arrived at Amboyua,
uly the 18th, 1693.

In the mountains of Ternata, a terrible noise is conti*
F 2



nually heard. The fire frequently casts out stones; and
lies exceeding deep. Probably the burning mountain*
in the Molucca islands are consumed beneath by the
.same fire.

Manilla is one of the largest of 'the Philippine islands
The city is much larger than Oxford, is an university
and is inhabited only by Spaniards. The houses are
large, and built very strong. The lower walls are stone
and of a prodigious thickness. All above is wood, anc
every piece of timber has a connexion with the others
and all are joined together, that the earthquakes which
are very frequent may not thro\%them down. In 1/50
they had an earthquake with almost continual trembling!
for three months. Then followed an eruption in a sinal
island, surrounded by a large lake, which is unfatliom
able. The third day after the eruption began, there
srose in the lake four more small islands, all burning
About a mile from one of these, there is a fire rising
continually out of the water, in a part where there
is no ground for above a hundred fathom.

11. A particular account of a journey to Mount
Hecla, is given by a late author. " We travelled/' says
he, " two days in rugged and unfrequented roads. Then
we came within six miles of the mountain, and perceived
the. ground strewed with ashes and pumice stone, over
which we passed to the foot of it. The weather being
serene and calm, and no fiames issuing out of the vol-
cano, we resolved to go to the top; till being informed
by our guides, that if \\e went any further, we should
be in danger of falling into pits, where we might be suf-
focated by the fumes rising out of the earth, all m)
company declined it. I told them, if they would stay
for me, I would 450 alone. They promised they would,
So I alighted and prepared to go up, when one of them
offered to go up with me.

" Having given our horses to our guides, who stayed
with the rest of our company, we ventured forward, re-


solving to reacli the top, and in a short time saw a large
flight of crows and vultures, that had their nest in the
top of the mountain. Having ascended about half a
league, we felt the ground shake under us, and heard a
terrible noise in the bowels of the earth, just as if it was
going to burst open. At the same time there appeared
on all sides chinks, out of which issued bluish flames,
with a strong suffocating smell. This made us turn
back, for fear of being burnt to ashes. But we had
scarce proceeded tlrrty yards back, before a black cloud
of smoke ascended out of the mountain, obscured the
light of the sun, and covered us so thick, that we could
not see each other. Our fears increased every .step we
took ,* for behind us came flames of fire, with showers

I of ashes and pumice stones, which fell as thick as hail.

I This dreadful storm was attended with horrible noises,
and we expected every moment the earth would open

I and swallow us up. This added wings to our flight, so
that in a quarter of an hour we got to the bottom of
the mountain/'

12. There are volcanos likewise in many of the
American islands ; and a very eminent one in Guada-
loupe. The summit of this constantly emits smoke,
and sometimes flames. It rises very high, in the form
of a cone, above the chain of mountains that occupy
the centre of the island. Near the foot of it are three
springs, the waters of which are so hot as to boil eggs
in three minutes. The neighbouring ground smokes/and
is full of brown earth, like the dross of iron. But the
chief place where the smoke issues out, is higher up, at
the foot of a steep bank, about fifty yards in breadth.
Here no grass is to be seen ; nothing but sulphur and
calcined earth. The ground is full of deep cracks,
which emit much smoke, and where you may hear the
sulphur boil. Bat the stench of it is m!o!erablc. The-
ground is loose, so that you may thrust a rane up
to the head, And when you draw it up, it will be as
hot as if you had plunged it into slaking lime.

On the plain top of the hill is another fnnuel, that
J? 3


opened some years since, and emits nothing but smoke.
Here are abundance of large and deep chinks, which
doubtless burned in former times. In the middle oi
this plain is a very ^ ep abyss. It is said there was
once a great earthquake in the island, and that the
Brimstone Hill (so they call it) then took rlre. It was
probably then this abyss was opened. It is between two
crags that rise above the mountain, and on the north side
answers to the great cleft, which goes down above a
thousand feet perpendicular, is more than twenty feet
broad, and penetrates above a hundred paces in the flat.
So that in this place the mountain is fairly split, from the
top down to the basis of the cone.

On this plain you may see the clouds gather below,
and hear the thunder rumble under your feet. The
great cavern is under the cleft, and was doubtless formed
by the same earthquake that split the mountain into two
parts nearly equal. The parting goes north and south.
To the north is the cleft and cavern, in the middle the
abyss, and to the south the burning gulph. The cavern
is above twenty-five feet wide, ad much in height, and
about sixty paces deep. Within this is a second ca?ve,
about sixty feet in length, as much in breadth, and forty
in height. Here the heat is moderate: but there is a third
cave within this, where it is so hot, that a torch will
give no light therein, and a man can scarce fetch breath.
Yet on the left is a great hollow, which is sufficiently
cool. And the space of one fathom makes the differ-
ence. It seems strange, that in the same cave, three
hundred feet under ground, it should be so hot on one
side, and so cool on the other. Perhaps the cool side
has some vent into the great cleft, and receives fresh air

] 3. Another surprising eminence, which may be ranked
among burning mountains, is the Pike of Tenerirle.
On the summit of it is a hollow, twelve or fourteen feet
deep : the sides, sloping down to the bottom, form a ca-
vity like a truncated cone, with its base uppermost.
This cavity is nearly circular* about forty fathoms across,


The ground is very hot, and, from near twenty vents, is-
sues a smoke of a strong sulphureous smell. The whole
soil seems powdered with brimstone, which forms a
beautifully coloured surface. Almost all the stones
thereabouts are of a greenish colour, sparkling with a
yellow, like gold. On the middle of one of the rocks
is a hole, about two inches in diameter. Hence pro-
ceeds a noise like that of a great body of liquors boil-
ing very strongly. And so hot a steam comes from it,
as will burn the'hand, even at a quarter of a yard's dis-

A small part of the sugar-loaf is white like lime ;
another small part is covered with salt. But the far
greatest part is covered with snow, almost throughout
the year.

The accounts given of its height are exceeding varu
ous. But a gentleman some years ago, who measured
it exactly, fouud the perpendicular height to be two
thousand five hundred aiad sixty-six fathom.

14. When it happens that any inflammable substance
takes fire in the caverns of the earth, the air contained
therein is rarefied and exploded with aa immense force.

Online LibraryJohn WesleyA survey of the wisdom of God in the creation; or, A compendium of natural philosophy .. (Volume 3) → online text (page 9 of 24)