Encyclopaedia Britannica > Volume 7, ETM-GOA

E T N [ 2 ] E T N
of a mixture of pozzolana with calcareous matters.
' At Lintini, and in places around it, there are diftinft
beds of pozzolana, fcorias, and real lava, as well as
others in which all thefe matters are blended together
in a mafs of calcareous matter. At Palazzolo, about
24 miles from the city of Syracufe, the fides of the
hills having been cut by the ftreams which run down
them, in many places to a confiderable depth, difplay
huge mafles of lava, and extenfive beds of pozzolana.
In the neighbourhood of Noto there are alfo volcanic
productions to be found.
At Pachino, where the ifland of Sicily forms an
angle, there are a range of hills extending for feveral
miles, which confift all of pozzolana.
The province of Val de Noto ft more homogene¬
ous in the matters of which its foil confifts, than the
two other dales of Sicily. Thefe, in every hill which
they contain, exhibit a vaft variety of different matters.
So amazing, indeed, is that variety, that they may be
confidered as exhibiting a collection of fpecimens of
all the different materials which enter into the compo-
fition of the globe. In thefe two dales few volcanic
productions have been yet obferved. But it is not to
be inferred for this reafon, that they contain but few.
They may be hereafter difcovered in great plenty. In
the volcano of water at Maccalubbe, between Ara-
gona and Girginti; in the baths of Caftellamare, near
Alcamo and Segefte ; in the baths of Termini, in the
ifles of Lipari; in the hot waters of AH, between
Meffina and Taormina, by the lake in the valley of
Caltagirone ; in all thefe places, which comprehend the
whole circumference of Sicily, the influence of the
volcano of Etna is, in fome meafure, felt. Nay, it
would even feem, that in thefe places there are fo riaany
volcanic craters. All of thefe are fo difpofed as to
fhow that they exifted f>rior not only to the volcanic
matters, but to the other fubftances intermixed with
them.
The waters of the fea have, in former times, rifen
much higher than at. prefent. But how they retreated,
or whether they are to continue ftationary at their
prefent height, we know not. For more than 2000
years, during which Sicily has been inhabited, and has
had cities and harbours, the fea has not been ob¬
ferved either to recede or encroach in any confiderable
degree.
When the fea fubfided from mount Etna, the moun¬
tain muft have been covered over with fuch matters as
the fea ufually depofits; confequently with calcare¬
ous matters. A part of thofe matters would be in¬
durated by the adtion of the atmofphere, while the
reft would be carried down by the rain-waters, and
again conveyed into the ocean. The torrents of rain¬
water which pour down the fides of mount Etna have
furrowed its fides, by cutting out for themfelves chan¬
nels ; and they have removed from its fummit, and are
ftill removing to a farther diftance, all the extraneous
bodies upon it. In many places, they flow at prefent
over a channel of lava, having cut through all tire
matters which lay above it: ftill, however, there re¬
main in many places both calcareous matter and other
marine productions, which fhow that this volcano has
been once covered by the waters of the ocean. But
thefe are daily wafting awayj, not only the rains, but
men likewife, who carry them off as materials for lime Etna-
and for building, confpire to deface them. v *
No fewer than 77 cities, towns, and villages, are
feattered over the fides of Etna. They are moft nu¬
merous on the fouth fide, where the temperature of
the air is milder than on the north. Reckoning thofe
cities, towns, and villages, one with another, to con¬
tain each 1200 or 1500 fouls, the whole number of
the inhabitants of mount Etna will then be 92,400,
or 115,500. But it is certainly much more confiderable.
On plate CLXXXIV. is exhibited a view of the Fig. r.
north-eaft fide of the mountain, taken at fea. The 1
lower part prefents to the eye very extenfive plains en- Atrcoimt^oF
tirely covered with lava of different thicknefs, on which
vegetation has not yet made any prqgrefs. The the moun-
nearer the fhore the more barren is the ground-; whiletain.
the fertility of the foil increafes as we advance farther
inwards. The mountain is every where full of vaft
excavations; which our author confiders as a proof,
that inftead of increafmg in bulk, it is actually in a 3
ftate of decay and diminution. The vaft torrents ofSuppofeff
lava, which overfpread the fides of it from time ta^° be
time, he confiders as infufficient to repair the wafteCaye °
occafioned by rains, rivulets, and torrents flowing down
from the fummit. Unlefs the eruptions, therefore, be¬
come more frequent than, they have been for fome
time paft, he fuppofes that, by degrees, the height of
the mountain muft be reduced to that of the furround¬
ing beds of lava. He had not an opportunity of mea-
furing the altitude of Etna himfelf; but he obferves
that it had been done by the celebrated M. de Sauf- 4
fure, who found the elevation to be 10,036 feet. This Sau flu re’s
was done on the 5th of June 1773, at 20 minutes af-a£co“n.t °£
ter feven in the morning. The height of the barome- 0££t^ *"
ter on the moft eL/ated part at the brink of the cra¬
ter was 18 inches 1 ij: lines ; which, by the neceffary
correftions, is reduced to 18 inches loj-y lines. At
the fame time the mercury at Catania, placed only one
foot above the level of the fea, ftood at 28 inches 2-fe¬
lines; which muft be reduced to 28 inches lines, on
account of the neceffary corredtions for the thermo¬
meter. ?
From Giana our author had an opportunity of con- Mountains
templating the vaft number of calcareous, mountsof caicare'
fcattered over that part of Etna; which (he fays)ous IBatter*
“ are nothing more than fragments, the flender re¬
mains of thofe enormous maffes which have been de-
pofited all around tke bafe of mount Etna ; and are a
very curious monument of the revolutions which this
mountain has undergone.*’ They are of a true calca¬
reous nature ; and the inhabitants are accuftomed to
fupply themfelves with limeftone from them. They
alfo ufe the ftones of which thefe mounts are com-
pofed for the purpofes of building ; as the lava is
fo hard that it cannot be cut without the greateft
difficulty, and they have no other ftone in thefe parts.
Leaving this place, our author travelled over leveral
extenfive plains of lava, covered on each fide of the
way with ftunted trees, but without any cultivation ;
the lava being of that kind which is very unfavourable
to the growth of vegetables. Arriving at St Le¬
onardo, he observed the courfe of the eruption of wa¬
ter in 1755, and which is mentioned under the former
article -L r:,'.v,
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