Chapter 8

PHYSICAL FEATURES OF THE MOUNTAIN.

Height.--Radius of Vision from the summit.--Boundaries.--Area.-- Population.--General aspect of Etna.--The Val del Bove.--Minor Cones.--Caverns.--Position and extent of the three Regions.--Regione Coltivata.--Regione Selvosa.--Regione Deserta.--Botanical Regions.-- Divisions of Rafinesque-Schmaltz, and of Presl.--Animal life in the upper Regions.

In the preceding chapter we have discussed the history of Mount Etna; the references to its phenomena afforded by writers of various periods; and the present state of the literature of the subject. We have now to consider the general aspect and physical features of the mountain, together with the divisions of its surface into distinct regions.

The height of Etna has been often determined. The earlier writers had very extravagant notions on the subject, and three miles has sometimes been assigned to it. Brydone, Saussure, Shuckburgh, Irvine, and others, obtained approximations to the real height; it must be borne in mind, however, that the cone of a volcano is liable to variations in height at different periods, and a diminution of as much as 300 feet occurred during one of the eruptions of Etna, owing to the falling in of the upper portion of the crater. During the last sixty years, however, the height of the mountain has been practically constant. In 1815 Captain Smyth determined it to be 10,874 feet. In 1824 Sir John Herschel, who was unacquainted with Smyth's results, estimated it at 10,872-1/2 feet. The new map of the Stato Maggiore gives 3312·61 metres = 10867·94 feet.

When the Canon Recupero devoted two chapters of his quarto volume to a discussion of the height of Etna, no such exact observations had been made, consequently he compared, and critically examined, the various determinations which then existed. The almost perfect concordance of the results given by Smyth, Herschel, and the Stato Maggiore, render it unnecessary for us to further discuss a subject about which there can now be no difference of opinion.

Professor Jukes says, "If we were to put Snowdon, the highest mountain in Wales, on the top of Ben Nevis, the highest in Scotland, and Carrantuohill, the highest in Ireland, on the summit of both, we should make a mountain but a very little higher than Etna, and we should require to heap up a great number of other mountains round the flanks of our new one in order to build a gentle sloping pile which should equal Etna in bulk."

The extent of radius of vision from the summit of Etna is very variously stated. The exaggerated notions of the earlier writers, that the coast of Africa and of Greece are sometimes visible, may be at once set aside. Lord Ormonde's statement that he saw the Gulf of Taranta, and the mountains of Terra di Lecce beyond it--a distance of 245 miles--must be received with caution. It is, however, a fact that Malta, 130 miles distant, is often visible; and Captain Smyth asserts that a considerable portion of the upper part of the mountain may sometimes be seen, and that he once saw more than half of it, from Malta, although that island is usually surrounded by a sea-horizon. It is stated on good authority that Monte S. Giuliano above Trapani, and the OEgadean Isles, 160 miles distant, are sometimes seen. Other writers give 128 miles as the limit. The fact is, that atmospheric refraction varies so much with different conditions of the atmosphere that it is almost impossible to give any exact statement. The more so when we remember that there may be many layers of atmosphere of different density between the observer and the horizon. Distant objects seem to be just under one's feet when seen from the summit of the mountain. Smyth gives the radius of vision as 150·7 miles: and this we are inclined to adopt as the nearest approach to the truth, because Smyth was an accurate observer, and he made careful corrections both for error of instruments and for refraction. This radius gives an horizon of 946·4 miles of circumference, and an included area of 39,900 square miles--larger than the area of Ireland. If a circle be traced with the crater of Etna as a centre, and a radius of 150·7 miles, it will be found to take in the whole of Sicily and Malta, to cut the western coast of Italy at Scalca in Calabria, leaving the south-east coast near Cape Rizzuto. Such a circle will include the whole of Ireland, or if we take Derby as the centre, its circumference will touch the sea beyond Yarmouth on the East, the Isle of Wight on the South, the Irish Channel on the West, and it will pass beyond Carlisle and Newcastle-on-Tyne on the North.

The road which surrounds the mountain is carried along its lower slopes, and is 87 miles in length. It passes through the towns of Paterno, Aderno, Bronte, Randazzo, Linguaglossa, Giarre, and Aci Reale. It is considered by some writers to define the base of the mountain, which is hence most erroneously said to have a circumference of 87 miles; but the road frequently passes over high beds of lava, and winds considerably. It is about 10 miles from the crater on the North, East, and West sides, increasing to 15-1/2 miles at Paterno, (S.W.). The elevation on the North and West flanks of the mountain is nearly 2,500 feet, while on the South it falls to 1,500 feet, and on the East to within 50 feet of the level of the sea. It is quite clear that it cannot be asserted with any degree of accuracy to define the base of the mountain.

The "natural boundaries" of Etna are the rivers Alcantara and Simeto on the North, West, and South, and the sea on the East to the extent of 23 miles of coast, along which lava streams have been traced, sometimes forming headlands several hundred feet in height. The base of the mountain, as defined by these natural boundaries, is said to have a circumference of "at least 120 miles," an examination of the new map, however, proves that this is over-estimated.

If we take the sea as the eastern boundary, the river Alcantara, (immediately beyond which Monte di Mojo, the most northerly minor cone of Etna is situated), as the northern boundary, and the river Simeto as the boundary on the west and south, we obtain a circumference of 91 miles for the base of Etna. In this estimate the small sinuosities of the river have been neglected, and the southern circuit has been completed by drawing a line from near Paterno to Catania, because the Simeto runs for the last few miles of its course through the plain of Catania, quite beyond the most southerly stream of lava. The Simeto (anciently _Simæthus_) is called the Giaretta along the last three miles of its course, after its junction with the Gurna Longa.

The area of the region enclosed by these boundaries is approximately 480 square miles. Reclus gives the area of the mountain as 1,200 square kilometres--461 square miles. (_Nouvelle Geographie Universelle_, 1875.) The last edition of a standard Gazetteer states it as "849 square miles;" but this estimate is altogether absurd. This would require a circle having a radius of between sixteen and seventeen miles. If a circle be drawn with a radius of sixteen miles from the crater, it will pass out to sea to a distance of 4-1/2 miles on the East, while on the West and North it will pass through limestone and sandstone formations far beyond the Alcantara and the Simeto, and beyond the limit of the lava streams.

There are two cities, Catania and Aci Reale, and sixty-two towns or villages on Mount Etna. It is far more thickly populated than any other part of Sicily or Italy, for while the population of the former is 228 per square mile, and of the latter 233, the population of the habitable zone of Etna amounts to 1,424 per square mile. More than 300,000 persons live on the slopes of the mountain. Thus with an area rather larger than that of Bedfordshire (462 square miles) the mountain has more than double the population; and with an area equal to about one-third that of Wiltshire, the population of the mountain is greater by nearly 50,000 inhabitants. We have stated above that the area of Etna is 480 square miles, but it must be borne in mind that the habitable zone only commences at a distance of about 9-1/4 miles from the crater. A circle, having a radius of 9-1/4 miles, encloses an area of 269 square miles; and 480 minus 269 leaves 211 square miles as the approximate area of the habitable zone. Only a few insignificant villages on the East side are nearer to the crater than 9-1/4 miles. Taking the inhabitants as 300,000, we find, by dividing this number by 211, (the area of the habitable zone), that the population amounts to 1,424 per square mile. Even Lancashire, the most populous county in Great Britain, (of course excepting Middlesex), and the possessor of two cities, which alone furnish more than a million inhabitants, has a population of only 1,479 to the square mile.

Some idea of the closeness of the towns and villages may be found by examining the south-east corner of the map. If we draw a line from Aci Reale to Nicolosi, and from Nicolosi to Catania, we enclose a nearly equilateral triangle, having the coast line between Aci Reale and Catania as its third side.

Starting from Aci Reale with 24,151 inhabitants, and moving westwards to Nicolosi, we come in succession to Aci S. Lucia, Aci Catena, Aci S. Antonio, Via Grande, Tre Castagni, Pedara, Nicolosi, completing the first side of the triangle; then turning to the south-east and following the Catania road, we pass Torre di Grifo, Mascalucia, Gravina, and reach Catania with 85,055 inhabitants; while on the line of coast between Catania and Aci Reale we have Ognina, Aci Castello, and Trezza. Within the triangle we find Aci Patane, Aci S. Filippo, Valverde, Bonacorsi, S. Gregorio, Tremestieri, Piano, S. Agata, Trappeto, and S. Giovanni la Punta: in all twenty-five, two of which are cities, several of the others towns of about 3,000 inhabitants, and the rest villages. These are all included within an area of less than thirty square miles, which constitutes the most populous portion of the habitable zone of Etna.

That the population is rapidly increasing is well shown by a comparison of the number of inhabitants of some of the more important towns in 1824 and in 1876.[15]

_1824_ _1876_

Catania 45,081 85,055 Aci Reale 14,094 24,151 Giarre 13,705 17,965 Paternò 9,808 16,512 Aderno 6,623 15,657 Bronte 9,153 15,081 Biancavilla 5,870 13,261 Linguaglossa 2,415 9,120 Randazzo 4,700 8,378 Piedimonte Etnea 1,404 4,924 Zaffarana Etnea 700 3,884 Pedara 2,068 3,181 Trecastagni 2,406 3,061

[15] I am indebted for these figures to Mr. George Dennis, H.M. Consul General for Sicily.

The general aspect of Etna is that of a pretty regular cone, covered with vegetation, except near the summit. The regularity is broken on the East side by a slightly oval valley, four or five miles in diameter, called the _Val del Bove_, or in the language of the district Val del _Bue_. This commences about two miles from the summit, and is bounded on three sides by nearly vertical precipices from 3,000 to 4,000 feet in height. The bottom of the valley is covered with lavas of various date, and several minor craters have from time to time been upraised from it. Many eruptions have commenced in the immediate neighbourhood of the Val del Bove, and Lyell believes that there formerly existed a centre of permanent eruption in the valley. The Val del Bove is altogether sterile; but the mountain at the same level is, on other sides, clothed with trees. The vast mass of the mountain is realised by the fact that, after twelve miles of the ascent from Catania, the summit looks as far off as it did at starting. Moreover, Mount Vesuvius might be almost hidden away in the Val del Bove.

A remarkable feature of Etna is the large number of minor craters which are scattered over its sides. They look small in comparison with the great mass of the mountain, but in reality some of them are of large dimensions. Monte Minardo, near Bronte, the largest of these minor cones, is still 750 feet high, although its base has been raised by modern lava-streams which have flowed around it. There are 80 of the more conspicuous of these minor cones, but Von Waltershausen has mapped no less than 200 within a ten mile radius from the great crater, while neglecting many monticules of ashes. As to the statement made by Reclus to the effect that there are 700 minor cones, and by Jukes, that the number is 600, it is to be supposed that they include not only the most insignificant monticules and heaps of cinders, but also the _bocche_ and _boccarelle_ from which at any time lava or fire has issued. If these be included, no doubt these numbers are not exaggerations.

The only important minor cone which has been produced during the historical period, is the double mountain known as Monti Rossi, from the red colour of the cinders which compose it. This was raised from the plain of Nicolosi during the eruption of 1669; it is 450 feet in height, and two miles in circumference at the base. In a line between the Monti Rossi and the great crater, thirty-three minor cones may be counted. Hamilton counted forty-four, looking down from the summit towards Catania, and Captain Smyth was able to discern fifty at once from an elevated position on the mountain. Many of these parasitic cones are covered with vegetation, as the names Monte Faggi, Monte Ilice, Monte Zappini, indicate. The names have not been happily chosen; thus there are several cones in different parts of the mountain called by the same name--Monte Arso, Monte Nero, Monte Rosso, Monte Frumento, are the most common of the duplicates. Moreover, the names have from time to time been altered, and it thus sometimes becomes difficult to trace a cone which has been alluded to under a former name, or by an author who wrote before the name was changed. In addition to the minor cones from which lava once proceeded, there are numerous smaller vents for the subterranean fires called _Bocche_, or if very small, _Boccarelle_, _del Fuoco_. In the eruption of 1669, thirteen mouths opened in the course of a few days; and in the eruption of 1809, twenty new mouths opened one after the other in a line about six miles long. Two new craters were formed in the Val del Bove in 1852, and seven craters in 1865. The outbursts of lava from lateral cones are no doubt due to the fact that the pressure of lava in the great crater, which is nearly 1000 feet in depth, becomes so great that the lava is forced out at some lower point of less resistance. The most northerly of the minor cones is Monte di Mojo, from whence issued the lava of 396 B.C., it is 11-1/2 miles from the crater; the most southerly cone is Monte Ste Sofia, 16 miles from the crater. Nearly all the minor cones are within 10 miles of the crater, and the majority are collected between south-east, and west, that is, in an angular space of 135°, starting midway between east and south, (45° south of due east) to due west, (90° west of due south). Lyell speaks of the minor cones "as the most grand and original feature in the physiognomy of Etna."

A number of caverns are met with in various parts of Etna; Boccacio speaks of the Cavern of Thalia, and several early writers allude to the Grotto delle Palombe near Nicolosi. The latter is situated in front of Monte Fusara, and the entrance to it is evidently the crater of an extinct monticule. It descends for 78 feet, and at the bottom a cavern is entered by a long shaft; this leads to a second cavern, which abruptly descends, and appears to be continued into the heart of the neighbouring Monti Rossi. Brydone says that people have lost their senses in these caverns, "imagining that they saw devils, and the spirits of the damned; for it is still very generally believed that Etna is the mouth of Hell." Many of the caverns near the upper part of the mountain are used for storing snow, and sometimes as places of shelter for shepherds. We have already seen to what extent Lucretius attributed the eruptions to air pent up within the interior caverns of the mountains.

The surface of the mountain has been divided into three zones or regions--the _Piedimontana_ or _Coltivata_; the _Selvosa_ or _Nemorosa_; and the _Deserta_ or _Discoperta_. Sometimes the name of _Regione del Fuoco_ is given to the central cone and crater. As regards temperature, the zones correspond more or less to the Torrid, Temperate, and Frigid. The lowest of these, the _Cultivated Region_, yields in abundance all the ordinary Sicilian products. The soil, which consists of decomposed lava, is extremely fertile, although of course large tracts of land are covered by recent lavas, or by those which decompose slowly. In this region the vine flourishes, and abundance of corn, olives, pistachio nuts, oranges, lemons, figs, and other fruit trees.

The breadth of this region varies; it terminates at an approximate height of 2000 feet. A circle drawn with a radius of 10 miles from the crater, roughly defines the limit. The elevation of this on the north is 2,310 feet near Randazzo; on the south, 2,145 feet near Nicolosi; on the east, 600 feet near Mascali; and on the west, 1,145 feet near Bronte. The breadth of this cultivated zone is about 2 miles on the north, east, and west, and 9 or 10 on the south, if we take for the base of the mountain the limits proposed above.

The _Woody Region_ commences where the cultivated region ends, and extends as a belt of varying width to an approximate height of 6,300 feet. It is terminated above by a circle having a radius of nearly 1-1/2 miles from the crater. There are fourteen separate forests in this region: some abounding with the oak, beech, pine, and poplar, others with the chestnut, ilex, and cork tree.

The celebrated _Castagno di Cento Cavalli_, one of the largest and oldest trees in the world, is in the Forest of Carpinetto, on the East side of the mountain, five miles above Giarre. This tree has the appearance of five separate trunks united into one, but Ferrara declares that by digging a very short distance below the surface he found one single stem. The public road now passes through the much-decayed trunk. Captain Smyth measured the circumference a few feet from the ground, and found it to be 163 feet, which would give it a diameter of more than 50 feet. The tree derives its name from the story that one of the Queens of Arragon took shelter in its trunk with a suite of 100 horsemen. Near this patriarch are several large chestnuts, which, without a shadow of doubt, are single trees; one of these is 18 feet in diameter, and a second 15 feet, while the _Castagno della Galea_, higher up on the mountain, is 25 feet in diameter, and probably more than 1000 years old. The breadth of the Regione Selvosa varies considerably, as may be seen by reference to the accompanying map; in the direction of the Val del Bove it is very narrow, while elsewhere it frequently has a breadth of from 6 to 8 miles.

The Desert Region is embraced between the limit of 6,300 feet and the summit. It occupies about 10 square miles, and consists of a dreary waste of black sand, scoriæ, ashes, and masses of ejected lava. In winter it remains permanently covered with snow, and even in the height of summer snow may be found in certain rifts.

Botanists have divided the surface of Etna into seven regions. The first extends from the level of the sea to 100 feet above it, and in it flourishes the palm, banana, Indian fig or prickly pear, sugar-cane, mimosa, and acacia. It must be remembered, however, that it is only on the east side of the mountain that the level within the base sinks to 100 feet above the sea; and, moreover, that the palm, banana, and sugar-cane, are comparative rarities in this part of Sicily. Prickly pears and vines are the most abundant products of the lower slopes of the eastern side of Etna. The second, or hilly region, reaches from 100 to 2000 feet above the sea, and therefore constitutes, with the preceding, the _Regione Coltivata_ of our former division. In it are found cotton, maize, orange, lemon, shaddock, and the ordinary Sicilian produce. The culture of the vine ceases near its upward limit. The third, or woody region, reaches from 2000 to 4000 feet, and the principal trees within it are the cork, oak, maple, and chestnut. The fourth region extends from 4000 to 6000 feet, and contains the beech, Scotch fir, birch, dock, plaintain, and sandworth. The fifth, or sub-Alpine region, extending from 6000 to 7000 feet, contains the barberry, soapwort, toad-flax, and juniper. In the sixth region, 7,500 to 9000 feet, are found soapwort, sorrel, and groundsel; while the last narrow zone, 9000 to 9,200 feet, contains a few lichens, the commonest of which is the _Stereocaulon Paschale_. The flora of Etna comprises 477 species, only 40 of which are found between 7000 feet and the summit, while in the last 2000 feet only five phanerogamous species are found, viz., Anthemis Etnensis, Senecio Etnensis, Robertsia taraxacoides, (which are peculiar to Etna), Tanacetum vulgare, and Astragulus Siculus. Common ferns, such as the _pteris aquilina_, are found in abundance beneath the trees in the Regione Selvosa.

This division has been advocated by Presl in his _Flora Sicula_.[16] He names the different regions beginning from below: _Regio Subtropica_, _Regio Collina_, _Regio Sylvatica inferior_, _Regio fagi Sylvestris_. These four are common to all Sicily. The three remaining regions, _Regio Subalpina_, _Regio Alpina_, and _Regio Lichenum_, together extending from 6000 to 9,200 feet, belong to Etna alone.

[16] "Flora sicula: exhibens Plantas vasculosas in Sicilia aut sponte crescentes aut frequentissime cultas, secundum systema naturale digestas." Auctore G. B. Presl. Pragæ, 1824.

At the conclusion of the first volume of Recupero's _Storia Naturale et Generale dell' Etna_ we find a somewhat different botanical division proposed by Signor Rafinesque-Schmaltz.[17] He makes his divisions in the following manner:--

1. Florula Piedemontana. 2. Florula Nemorosa. 3. Florula excelsa o della Regione Discoperta. 4. Florula Arenosa o della Regione delle Scorie.

[17] Chloris Aetnensis: o le quattro Florule dell' Etna, opusculo del Sig. C. S. Rafinesque-Schmaltz, Palermo. Dicembre, 1813.

In the latter region, (to which he assigns no limit as to height), he found Potentilla Argentea, Rumex Scutatus, Tanacetum Vulgare, Anthemis Montana, Jacobæa Chrysanthemifolia, Seriola Uniflora, and Phalaris Alpina.

As regards the animal life on Etna, of course it is the same as that of the eastern sea-board of Sicily, except in the higher regions, where it becomes more sparse. The only living creatures in the upper regions are ants, a little lower down Spallanzani found a few partridges, jays, thrushes, ravens, and kites.

Brydone says of the three regions: "Besides the corn, the wine, the oil, the silk, the spice, and delicious fruits of its lower region; the beautiful forests, the flocks, the game, the tar, the cork, the honey of its second; the snow and ice of its third; it affords from its caverns a variety of minerals and other productions--cinnabar, mercury, sulphur, alum, nitre, and vitriol; so that this wonderful mountain at the same time produces every necessary, and every luxury of life."