VESUVIUS, a volcanic mountain, situated in the kingdom of Naples, about six miles to the eastward of the capital. By the ancients it was called Mons Vesevus, or Vesbius, and in the earlier ages of antiquity, it was famed for the luxuriance of the vegetation with which its sloping sides were covered, as it also is in modern times, except in those spots laid waste by recent streams of erupted lava. On three sides, the mountain overlooks the rich plain, termed from its exquisite cultivation, and the diligence of its peasantry, with equal propriety the Terra di Lavoro, and the Campo Felice, while on the fourth, it descends more abruptly to be washed by the waves of that splendid expanse of water, to which it adds so high a charm, the Bay of Naples, its base here being covered by a connected chain of large villages, forming a stretch, perhaps almost unexampled, of many miles.

In regard to geological position, several important facts are to be noticed; and in the first place, the whole tract of country, within several miles in every direction landward of Naples, which has all the same general constitution as that small portion called the Phlegræan fields, must be considered as a formation subordinate to its main feature, Mount Vesuvius, as owing its existence to essentially the same phenomena, and as an actual superposition of a tract of country upon the pre-existent chain of the Apennines, which probably was at one period washed by the sea. The western limit of the Bay must then have been the Monte Massico, not far from Mola, instead of the island of Ischia, which now terminates it, the eastern limit or the promontory of Minerva remaining constant, which gives an opening more than double the present one, and the extreme depth of the bay, full fourteen miles greater. The whole volcanic formation of which Vesuvius forms the focus, reposes therefore upon the secondary limestone of which the Apennine range is here formed; and of this we have various direct proofs, the most remarkable of which is the frequent projection of calcareous masses from the crater of Vesuvius, either in an unaltered or a modified state; we have therefore the conclusive certainty, that between the volcanic focus and the point of eruption, there exist calcareous strata. The proximity of this volcano to the sea likewise deserves notice, as following the general law pointed out in the article PHYSICAL GEOGRAPHY. "Volcanoes," it is there remarked, "seem in general to be situated near the sea-coast, and rarely or never in the interior of large continents. Catopaxi, in South America, is perhaps, of all volcanic mountains, the most distant from the ocean, and yet it is only 140 miles distant from the shores of the Pacific.' This is one of the few general facts recognised in connexion with the theory of volcanoes, and ought therefore to hold a place commensurate

with its importance in hypothetical reasoning on this subject.

In taking a general view of the external features of Vesuvius, we are in the first place struck by its remarkable separation into two very dissimilar parts; Vesuvius, properly so called, a cinerous cone rising from an irregular plain, situated at no less than 2400 feet above the sea, and Monte Somma, a craggy range of rocks, the precipitous side of which is formed into the segment of a circle, and presents its concavity towards the cone of Vesuvius, which it flanks to the northward for a considerable extent, its own north side sloping gradually down to the plain of the Campo Felice. It is similar, in many respects, to the remarkable hill of Salisbury Crags near Edinburgh, if we conceive the perpendicular face of the latter to have a concave instead of convex horizontal projection, and instead of the debris which form the steep slope to the westward, a plain be conceived to extend from the base of the precipitous rock till it joins the cone already mentioned.

Monte Somma appears undoubtedly to have been the primeval point of ejection, though the conjecture of some authors, that the present concavity formed the wall of a part of the original crater, seems extravagant, as the circle of which it is a segment would have had a circumference of many miles. Some traces of what may have been the original crater may be observed in the course of this precipitous range near its western extremity. The face of rock there presents a remarkable section, the main body being traversed by dykes which pursue contorted courses, and frequently merge into or cross one another; they are of a different species of rock from the basis, and may probably owe their origin to fissures made by the subsidence of the upheaved pre-existent rock, and filled up by a new species of lava at the next eruption. See Saussure in the Geneva Transactions, vol. ii.; Sir James Hall in the Edinburgh Transactions, vol. vii.; Hamilton's Campi Phlegræi, and the Edinburgh Journal of Science, vol. ix. p. 191. The extreme height of

the Somma is 3703 feet.

At the western extremity of the Somma, rises an elongated tufaceous eminence, named Monte Cantaroni, on which at an elevation of 1971 feet, stands the well known hermitage of St. Salvador, and which is said to have been thrown up by the eruption of A.D. 79, when the whole features of the volcano seem to have been changed, and when the present position of the cone probably first became the point of emission. This spot is protected from the effects of streams of lava which often pass near it, by a valley on each side, which serve to guide the torrent in different directions; one of these is called the Fossa di Faraonte, the other Fossa Grande; Fossa being the name here for these deep and narrow ravines with which Vesuvius abounds;

the latter of these is interesting from the vast abundance of simple materials which it affords.

The cone, or Vesuvius properly so called, next demands attention. Its height is liable to considerable variation from the explosive effects of erup tions which have been known to carry off at once 800 feet of perpendicular height of the summit. The Abbe Nollet in 1749 found the height above the sea to be 3120 French feet, while Della Torre in 1752 gave from his very imperfect measurements with the barometer only 1677 feet, a singular proof of the enormous errors which at that period might be committed without immediate detection. The first good observation we have is that of Saussure, making the height 3659 French feet, which is very interesting, by showing, as Humboldt has remarked, that this level is more constant than we are apt to imagine. Shuckburgh found the edge of the crater from which the lava of 1776 flowed to be 3692 French feet 3935 English. The point which Saussure measured was on the N. W. side of the crater, and from a post which was fixed upon it was named La Rocca del Palo. In 1805 Gay Lussac found this point 3757 English feet, and Lord Minto in 1821, 3963, and at that time, forty-nine years from its first measurement, it was carried away by the great eruption. To methodize the results with as much accuracy as the nature of the operations in general warrants, we give the height of the Rocca del Palo by different observers, in toises merely (6.3947 English feet) from a late work of Humboldt's.*

There is an appearance of greater elevation during the latter part of this period, which Humboldt thinks may amount to 12 toises, to be considered a proof of gradual internal elevation.

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The proportion of the cone of ashes to the total height is in Vesuvius nearly, whereas in the volcano of Pichincha, it is only 1%, and in the Peak of Teneriffe so low as 2. The mean slopes of volcanic cones are, according to Humboldt, from 32, to 426; the mean slope of Vesuvius between the summit and the Atrio del Cavallo, is probably equal to the highest of these values. The base of the cone is about 2480 feet above the sea.

The crater by which the cone of ashes is truncated, has varied in character and dimension very much, according to the state of the volcano. Subsequently to the eruption of 1822, when so vast a

• Tableaux de la Nature.

portion of summit was carried away, the crater has been, according to general computation, no less than three miles and one-third in circumference, and 1500 feet deep; being probably the largest in existence. This confirms the view given under the article PHYSICAL GEOGRAPHY, (Vol. XVI.), that, generally speaking, the size of craters is inversely as the height of the mountains to which they belong; even the case of Pichincha, which has a crater a mile in diameter, there quoted as an exception, we now see outdone in the comparatively diminutive example of Vesuvius. The American volcano is no less than four times as high as that of the Bay of Naples, or near 16,000 feet; Mount Etna, which has an elevation of 11,000 feet, had in 1769 a crater only 24 miles in circumference, and that of the Peak of Teneriffe, which has a height of above 12,000 feet, is only 300 feet long, 200 broad, and 100 deep.

The edge of the crater is narrow and precipitous, sloping internally and externally so fast, as to leave but a small ridge to walk upon. As to height, it is very irregular, the northern point being 500 feet higher than the southern. The depth of the crater below the lowest edge, is probably little less than 1500 feet, from which some idea of the true size of this vast chasm may be formed. The southern side presents so moderate a slope inwards, that without any peril, the traveller may descend till within about 500 feet of the bottom, where he is stopped by a precipitous crag; in the opposite direction it is so steep, that we cannot descend above a few paces. Various, indeed, are the modifications which the crater has assumed under different stages of volcanic energy. Previously to the first recorded eruption of A.D. 72, the summit exhibited, according to Strabo, a level plain, interspersed with rocks and caverns, which were rightly interpreted, as bearing marks of previous imflammation. Before the great eruption of 1631 took place, which succeeded to a long period of repose, the crater exhibited the most deceptive marks of quiescence; it was then 5000 paces round, and 1000 deep; in the bottom was a plane where cattle grazed, and the banks were clothed with abundant forests, in which wild boars took shelter, and afforded sport to the lovers of the chase. The sloping path which led to the bottom is said to have been three miles long. Three small lakes existed there, of which, according to the report of contemporary writers, one was warm, another salt, and the third bitter. It appears from the curious old representation of the mountain at this period, copied into Mecatti's account of Vesuvius, that the Monte Somma was covered with trees to the top, as was also the base of Vesuvius. In 1660 the crater was so shallow that it was easy to descend to the bottom, where a small cone was raised by the immediate action of the volcano. In 1755, the bottom was only 23 French feet below the edge, and from the centre rose a parasitical cone 80 or 90 feet in height, with its own proper crater. How different these conditions were from the present one, the dimensions already given will show.

↑ Humboldt's Personal Narrative, I. 207.

In order to convey a general idea of the features of this volcano, we shall give a brief account of the ascent, which is a matter of no difficulty, and may easily be accomplished by ladies.

There are different tracks by which the mountain may be ascended, but that universally preferred is by Resina, and it alone we shall describe. This village lies at the base of the mountain near the sea-shore, and is about six miles east of Naples. Here the traveller may think himself fortunate if he can secure the personal attendance of the elder Salvatore, one of the best guides who can be met with for any such expedition; asses are usually taken to diminish the labour of the ascent. For some way the road is simply rugged and stony, bounded by high walls inclosing those extensive vineyards which produce the admirable Lacryma Christi of this vicinity; currents of lava will occasionally meet the eye of the traveller, and on the right hand he will remark an unfortunate house, one half of which has literally been swept away by such a stream, whilst the other has been left entire, as if to tell the tale. Farther on, cultivation in a moment ceases, and all the luxuriance of nature and of art combined is exchanged within a few yards for a degree of obdurate sterility in the one which bids defiance to all the ameliorating efforts of the other. In a word, we have reached the western extremity or embouchure of the Atrio del Cavallo, and we see stretched before us the combined streams of the eruptions of 1767, 1771, 1819 and 1822. The last is not here so strikingly repulsive as higher up the valley, as we shall presently describe; that of 1819 is remarkable for the peculiar ropy form which it has assumed, being nothing else than the effect of successive waves of scoriaceous matter forcing up the imperfectly solidified substance of the preceding ones; hence it has acquired the appropriate name of "Lava Corde." Near it may be seen rudely intermixed tabular masses; these have been produced by the insinuation of a liquid stream below a thin but solid crust of lava which it has shattered, and then recombined the fragments. A few lichens on the lava of 1767, are all the marks of decomposition which it yet exhibits, and those on the current of 1819 are little better than microscopic; yet even these are farther advanced than some other lavas in the Bay of Naples which have lain exposed for centuries. We next reach the Monte Cantaroni already mentioned, which presents a steep ascent; the highest point of this huge protruded mass of tufa is Occupied by the hermitage of St. Salvador, where the monks live, who rather lead the life of publicans than eremites.* It is to be observed, that coming to Monte Cantaroni at all, is quite out of the direct line of ascent, for we must again cross the Atrio del Cavallo; but besides having the benefit of some species of road, the traveller who wishes to see the mountain, will do well to make this digression. Leaving St. Salvador, we pass near the "Cratere del Francese," where in 1819 an unfortunate Frenchman, after living three days at the her

mitage, plunged into the boiling abyss of lava, and met a fiery grave. Once more descending from the tufaceous eminence to the plain, we leave to the left the Monte Somma, and "Fossa di Faraonte," into which flowed the lava of 1785, and which divides it from Monte Cantaroni, and set our faces towards the cone of Vesuvius.

It is impossible to convey any impression of the state of this broad plain to those who have not visited similar scenes. The amorphous mass of stony matter deposited by the last great eruption (1822) has an appearance of sterility which no other rocky formation presents; and for this plain reason, that upon these natural causes of gradual but sure degradation have been working for thousands of years, while here the newly moulded matter is ejected unformed and intractable as when it so lately existed in the bowels of the earth. The small scale of artificial penetration of the strata at which human labour has arrived, can convey no idea of their primeval form: the difference lies in the comparative symmetry of our mining operations as well as in the trifling extent of surface they present; but this valley consists of several square miles, and the entire western portion is buried under this stony inundation, hard, black, and rugged, sometimes swelling into craggy eminences with narrow cavernous hollows between, or occasionally flowing in a thinner stream over the flat-bed prepared for it by the pre-occurrence of a tremendous shower of ashes, above which it has formed blistered cavities, into which shoot spicular masses of the same dark intractable material. The only variety with which the eye meets in this great plain, is here and there an ejected mass of many cubic yards content, discharged from the mountain with such explosive force as to be driven far from the base of the cone: all else has but a symmetry in horror. Nature here wants the majesty and elevation of rocky cliffs, or the rich coating of verdure, or the more interesting struggle of vegetable luxuriance with an arid soil, although but little removed from the fertile slope of the hill and the vast expanse of the highest cultivation which environs its base, these beauties only contrast the more with the dark, cold, monotonous lava of which the distorted forms seem to partake of mobility, were we not assured by our senses that it were the work of centuries to reduce the rugged configuration of this siliceous rock.

Arrived at last at the foot of the cone of ashes, the traveller must leave his mule or ass, and trust to his feet in ascending that fatiguing, though in the present state of the mountain, short ascent. An active man may accomplish it in thirty minutes, though not without great labour, from the sinking and sliding of the volcanic ashes. His trouble, however, will soon be overpaid by the spectacle which awaits him on reaching the summit. first he will naturally look inwards towards the crater at which he has at length arrived. Its vast magnitude, the ruggedness of its extreme edge, the appalling abruptness of the precipice from the

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summit of which he first obtains his view, the loud and repeated echoes which the shrill voices of the guides excite through the cavern, and the curling smoke rising from the abyss, often concealing by its dense volumes the remote recesses, and not unaccompanied perhaps, with internal boiling of the igneous fluid, the chance ejection of stones, or the occasional fall of rocks, the noise of whose descent is responded to by a hundred cliffs, all makes the scene one, the first impression of which is so noble, so striking, as perhaps is not to be renewed. But let him examine the structure more closely. In the late state of the mountain (we speak of the years 1826-7), he might without the shadow of danger descend two-thirds of the depth of the crater, by walking round a semi-circumference of it till he arrives at its south-eastern point. There the internal side, instead of presenting the abrupt precipice of its opposite extremity, shelves gradually inwards, aided by the much reduced elevation of its edge, which differs more than 500 feet from the N.W. point. Here we may descend till we reach a precipice 500 feet in height, which separates us from the bottom; and from this lone and unfrequented spot we may at leisure survey nature in some of her most remarkable forms. We tread amidst thick beds of sulphur, the crevices of which often emit steamy spiracles rapidly condensed by the chillness of the air, which is frequently great even amidst these subterranean fires. The shades of colour which the sulphur beds present, are most varied and beautiful, from the palest straw colour, where the pure yellow is diluted with the white deposits of decomposed lava, and occasionally of sulphate of alumina, up to the rich orange, which the intermixture of arsenic, forming red and yellow orpiment, occasionally presents. But grander scenes and sterner formations withdraw the attention of the observer from the mineral world immediately beneath his feet. He has but to raise his eyes to see the distended jaws of this great abyss stand in all their ruggedness before him. Huge misshapen crags rise on either hand, only their salient points conceal the remoter trendings of that volcanic plain which stands poised over unfathomed caverns, the laboratories of Cyclopian energy. The plateau of the crater is indeed but a crust, of which upon any excess of volcanic explosive force below, we have abundant proof by the formation of miniature craters, through which may be distinctly heard on such occasions, the boiling noise of internal agitation, and the rattling of stones, elevated from the pit, with the constantly succeeding columns of smoke which are the consequence. Nature seems to have completely barred the volcanic plateau from the access of mortal foot, in the present state of the mountain, yet the hardihood of strangers sometimes induces them to descend by means of ropes these tremendous natural ramparts, with the great danger of detaching masses of rock in the course of their descent. In this, as in all other enterprises of which empty vanity in personal achievement is the only excitement, we regret to add, our country

men predominate in numbers: whether the task be to scale the frozen summit of Mont Blanc, or grap ple with the embryo thunderbolt at the very forge of Vulcan; or the easier feat of scratching initials on the Ball of St. Peter's,-in every act of vain-glorious temerity the English name is pre-eminent.

From the edge of the crater the distant view is almost equally worthy the traveller's attention in surprising contrast with the spectacle of its interior: there the rudest elements employed in the laboratory of nature, the unformed heap, the chaotic confusion, the groaning or thunderous sounds as of Nature's throes:-here robed in her fairest forms and hues, displaying all the beauties of recondite arrangement, and refined collocation of parts; the riches of her different kingdoms combined to form as it were a model of inartificial perfection. At sunset especially the scene may be most fully appreciated; the further beams of the great luminary as he sinks behind the remote shore of Gaeta, gild the distant waves of the Tyrrhene Sea, and invest the more abrupt points of the Italian shore with a halo of misty splendour. Nearer the eye, they throw long shadows from higher eminences in the Bay of Naples, the island of Ischia with its once volcanic summit, formerly much more to be dreaded than the now active Vesuvius; the hill of the Camaldoli; the humbler ridge of Pausilipo. The ancient craturs of Averno and Agnano, now occupied by lakes, demonstrate their true form by their deepening shadows, the domes and spires of Naples, and the old grey turrets of the Castel St. Elmo receive, and part with the declining solar ray, and whilst on the left, the towering hills of the promontory of Minerva, which form the eastern wing of the Bay, blaze in the broad expanse of sunshine, the distant Apennines behind the spectator as he faces the setting luminary, sink in the greyness of the twilight, and are soon lost in the dewy mists of the horizon.

The phenomena of eruptions are in all volcanos perhaps, very similar in a general view. Preceding earthquakes, subterranean noises, drying of wells, occasionally retirement of the sea, intimate the near approach of the catastrophe, and these are succeeded by heaving and splitting of the mountain, stillness and cloudiness in the air, accompanied with a highly electric condition, which imparts to the eruption some of its most extraordinary accessory phenomena. The explosive force from below having opened a rent in the crater, a vast discharge of gaseous fluids follow, and though not unoften accompanied by boiling water in streams, Vesuvius more frequently discharges showers of dry impalpable volcanic dust, so fine as to be sustained a considerable time in the higher regions of the atmosphere, where having attained the height at which the continued force of gravity and the diminished density of the air overcome the projectile momentum, the thin tall stream accumulates and spreads, having something of an umbrella form, or more accurately, that of the Italian pine (Pinus Pinea) to which it was first compared by Pliny, and

for which this mountain has ever been remarkable.* The dusty particles then descend over a vast extent of country, in a thick shower. It rarely happens that the crater is in a state to afford a ready over flow of lava, and therefore from the simple principles of hydrostatic pressure, that fluid bursts for itself a point of emission near the base of the mountain, and frequently elevates a parasitic cone. Thus the lava of 1794 (that dreadful eruption which last overwhelmed Torre del Greco) issued from a crack at the base of the cone, on the Pedamentina, about half a mile in length according to Breislak, and 100 yards wide. In the eruption of 1760, no less than fifteen mouths opened on the southern side of the mountain, raising as many cones, but the number of which was soon reduced to seven, and finally to four, the height of one of which is 200 feet. Again in the great eruption of 1822, several small cones were raised in the Atrio del Cavallo, between Vesuvius and the Hermitage.

Referring for more detailed accounts of particular eruptions, or of their general features, to the works of Hamilton, Breislak, Della Torre, Mecatti, and Scrope, we may mention the connexion which has been supposed to exist between Vesuvius and other volcanic emissaries. This question is a very important one, yet is still involved in considerable doubt. Breislak, who had the best means of judging, strenuously denied it, but we must suspect his judgment to have been biassed by preconceived opinions, from the general conception of the reverse which prevails respecting the connexion at least of Vesuvius and Solfatara, a sentiment which we ourselves have had the means of confirming, and which Sir Humphry Davy, a philosopher whose temperate judgment must ever command respect even for his hypotheses, expressly countenances. He observed the Solfatara on the 21st February 1820, two days before the eruption of Vesuvius was at its height; "the columns of steam," says he, which usually rise in large quantities when Vesuvius is tranquil, were now scarcely visible, and a piece of paper thrown into the aperture did not rise again, so that there was every reason to suppose the existence of a descending current of air." It might however be supposed, that the connexion of two volcanoes so nearly approached as Vesuvius and Etna, would be more defined than it appears to be. Among 50 eruptions of the former, and 48 of the latter, occurring since the Christian era, the following are the nearest coincidences.§

We must next very briefly notice the more important mineral productions of Vesuvius, confining ourselves to those of great extent and volcanic origin. These may be divided into lava, breccia, tufa, and volcanic dust.

Of a few of the external forms of lava we have already given some notice. The really ornamental lavas are chiefly found in the Mount Somma, and constitute the remarkable dykes or veins to which we have also referred; they consist of a compact basis imbedding many beautiful and perfect crystals of leucite, a mineral, nearly, if not altogether, confined to the volcanoes of Italy: they are called partridge-eyed lavas, and have a beautiful appearance. The Vesuvian lavas, for the most part, are hard and compact, and frequently approach in appearance to a perfect identity with some of our greenstones and basalts. Hence it is much used for paving, and the road between Naples and Portici is a perfect specimen of this application. It is quarried from the couleè of 1794, near where it flowed into the sea, and here a striking tendency towards the assumption of prismatic forms may be observed, and it is even probable that excellent cabinet specimens, having the columnar structure, might here be obtained; nothing indeed can more perfectly resemble a quarry of basalt; and the chain is so complete through the medium of the lava of Capo di Bove near Rome, and the extinct volcanoes of Auvergne, that the question of their similarity of origin is probably for ever set at rest. The varieties of lava found in Vesuvius is very great, and not less than twenty-two very distinct ones have been enumerated in the Monte Somma alone. In general, however, they are rough, opake, and without lustre, very rarely indeed presenting the vitreous lustre. Hence obsidian is one of its most uncommon products, though met with in considerable quantity in the neighbouring island of Ischia; it is only, we believe, found in small ovoidal cavities, principally confined to the leucitic lavas of the Monte Somma, and from that point of ancient emission the small quantity of pumice which is found in detatched masses on the mountain, seems also to have proceeded; these two minerals being probably very nearly allied in their formation. Lava highly cellular is not an unfrequent production of Vesuvius, and small spheres of it are frequently ejected along with volcanic sand, and by their lightness reach great distances. The cavities are occasionally coated with muriate of copper, as in specimens from the "Cratere del Francese.”

In the crater, lava exhibits a very different form; the action of heat and moisture, but especially the acid vapours which are abundantly evolved, soon effect the disruption of those affinities by which the compact condition of the rock was maintained. The most powerful agent is sulphurous acid, which at the same time, forming a neutral salt with the iron, which is by far the most abundant colouring

↑ Voyage Physique dans la Campanie, ii. 70.

Daubeny on Volcanoes, p. 216.