From the London Review.

DESCRIPTION OF ACTIVE AND EXTINCT VOLCANOES.*

"Where'er you tread, the raging fire

Flames underneath a treacherous ash."
The number of volcanoes active and

semi-extinct (called by the Italians, solfa-
turas) can not be precisely, but may be
approximately, stated. We present a
tabular view derived from two authors,
Girardin and Huot, (the latter cited by
M. Quatrefages.). This tabular view will
also show the geographical distribution of
continents and islands.
volcanoes, and their numerical relation to

PARTS OF
THE WORLD.

CON CONTINENTS. ON ISLANDS.

TOTALS.

Girardin. Huot. Girardin. Huot. Girardin. Huot.

"THE wonder which exceeds all others," observes Pliny, "is that the earth exists a single day without being burnt up." If this was the greatest marvel of the Roman naturalist, with his limited and imperfect knowledge of volcanic phenomena, surely it may be ours in a period when at least a superficial knowledge of volcanic action upon the face of our globe is so widely extended, and when, by laborious and accurate researches into the agency of terrestrial heat, we have analogically arrived at a fair conception of what lies under our feet, and what may be the thermal condition of the central portion of our globe. Supposing the views generally entertained by natural philosophers respecting the incandescence of the greater part of the interior of our planet to be correct, then we all walk, not upon "the solid earth," as is commonly said, but upon a mere pellicle of cool matter, the thickness of which, when compared with that of the earth, would represent little more than one inch It is very difficult to determine even for a globe whose diameter is about nine yards. In another form of illustration, approximately the number of active volour cool and firm crust does not much ex- since travelers disagree in attributing accanoes on the globe at the present time, ceed the proportion of the thickness of a sheet of ordinary paper, as compared with tivity to particular examples; some reone of the large globes employed for geo-sider to be in force. A list of those now garding those as extinct which others congraphical tuition. In a sense, then, far truer than Horace ever dreamed of when he sung the strain, we may say to every sojourner upon our globe:

“Incedis per ignes Suppositus cineri doloso."

*

* Description of Active and Extinct Volcanoes. By CHARLES DAUBENY, M.D., F.R.S. 8vo. Second Edi

tion. 1848.

Historical and Topographical Map of the Eruptions of Etna, from the Era of the Sicani to the present Time, (1824.) By JOSEPH GEMELLARO.

Carta Topographica dell' Etna, (with the Atlas.) Per il BARONE SARTORIUS DI WALTERSHAUSEN. Sicilia, 1836 al 1843; and Berlin, 1845.

Rambles of a Naturalist. By A. DE QUATREFAGES. (Translated.) Two Vols. 1857.

We merely represent current views on this point. Our own would rather tend to coïncide with those of Mr. Hopkins, which are the result of profound mathematical investigation, and can not be

here stated.

Europe...
Africa...

Asia...

America..
The Ocean.

Totals...

47281

4

55

18

114

108 182 108

182

109 186 194 878 808 559

presumed to be active is to be seen in 270, of which 190 are found on the islands Johnston's Physical Atlas, and it includes

or around the shores of the Pacific Ocean. Sir Charles Lyell estimates the eruptions of all known volcanoes to amount, on an average, to twenty every year. Of those volcanoes which are situated upon the islands of the sea, (nearly 194 according to Girardin, and 373 according to Huot, that is, according to both estimates, about two units of the whole number - many occur in plains but little elevated above the level of the sea, and at considerable distances from other mountains, so as to appear isolated. When so situated, it may be fairly presumed, that the volcanic mountains have risen from the bottom of the sea by the effects of the subaqueous agency, and that the plains which surround

them have been raised above the level of for upon consulting a list of the known the sea by the gradual accumulation of explosions of Vesuvius and Etna, (as tabthe materials ejected from the orifices of ulated by Hoff and Daubeny,) from the the volcanoes. In support of this view, date of the earliest recorded eruptions of the upper layers of the soils of such plains Etna, namely, B.C. 480, 427, and 396, and are almost entirely composed of material continued down to the year 1842, we find, derived from the deposition of volcanic from a comparison of the whole, that these matter, and they rest on a thick stratum eruptions exhibit little synchronism, and of such matter. We shall presently ex- that the nearest coincidence was in 1694 plain Von Buch's theory of upheavals in and in 1811, when the outbursts from these connection with a description of Etna. mountains occurred within a month of He was the first to show that large volca- each other. On eight several occasions noes did not originate from the simple ac- an interval of less than half a year apcumulation of these products, but that they peared between them, but no other strikhad been elevated together with the con- ing coincidences appear; and therefore we solidated masses. Several volcanoes seem regard each as a central volcano of a conto be the fiery centers of a large volcanic nected system, dissociated from other district, which surrounds them in circles systems. of greater or lesser extent. These are generally the loftiest peaks of whole groups of craters which are crowded together, and of which one or other has at some time shown signs of activity. Among such central volcanoes are Vesuvius, Etna, the Peak of Teyde in Teneriffe, the Pico of the Azores, the volcano of the Isle of Bourbon, famous for its mighty and frequent outbursts; Mount Erebus, about 12,500 feet high, discovered not many years since in the Antarctic Ocean, under south latitude 78°; and Mouna Loa, with Mouna Kea, in Hawaii, which are about the highest known island mountains, reaching, as they do, the one to an elevation of 13,760 feet, and the other to 13,950 feet, above the level of the sea. The crater on one of these mountains will presently be the subject of our description.

With reference to the small crater cones which surround a central volcano, we are generally acquainted with one eruption of each, namely, that to which they owe their origin, and before and after which the volcanic agency has found an outlet at some other point, more or less distant. Thus the whole group of the Canary Islands rests upon one volcanic hearth, over which each of these islands was reared up from the bottom of the sea.

All that has been observed of Vesuvius confirms the opinion that, together with the Phlegræan fields of Puzzuoli, and with the neighboring islands, it forms a single volcanic district, of which the mountain itself is the center, and that an outburst at any particular spot within this circle tends to prevent another in any other part of the same district. But we can not extend this connection beyond the particular district;

A considerable number of fiery mountains lie in a line one after another, in a long cleft rent through the crust of the earth; and they are frequently grouped in double rows or chains, which bound a greater or less extent. Such have been called linear or chain volcanoes. To this denomination belong the numerous volcanoes of Iceland, of which at least seven are still considered to be partially active, the highest mountain in Iceland being one

namely, Peräfa-Jökul-five thousand six hundred feet in hight. In other parts of the volcanic belt that runs across this island, enormous clefts have been torn open, from which streams of lava have flowed forth to a length and breadth which have scarcely been equaled in any other volcanic country. At the extraordinary eruption of Skáptar Jökul* in 1783, three fire-spouts rose high in the air, and then formed a torrent of burning lava, that flowed steadily for six weeks, and ran a distance of sixty miles to the sea in a broken breadth of nearly twelve miles. The Lipari Isles appear to be the loftiest crater-crests of a volcanic tract of considerable length, among which Stromboli is ever active. The western row of the lesser Antilles forms a connective chain of volcanic islands. On the continent of America a great number of burning mountains rise up upon the ridge of the Cordilleras. They generally form the highest portions of the mountain crests, and twelve may be regarded as chain volcanoes. Of these are the long row of Chilian volcanoes, of which Aconcagua, nearly in the latitude

*Skáptar Jökul, or Yokul, signifies "Snow Mountain."

of Valparaiso, is twenty-four thousand feet | first in a westerly direction for nearly two in hight. These volcanoes stretch almost hundred geographical miles, and then in a straight line along the coast, from 46° southwards, without interruption, throughto 29° south latitude. out a space of between sixty and seventy degrees of latitude, to the Moluccas, where it sends off a branch to the south coast, while the principal train continues westerly through Sumbawa and Java to Sumatra, and then in a north-westerly direction to the Bay of Bengal. This immense volcanic line may be said to follow throughout its course the external border of the continent of Asia; whilst the branch striking south-east from the Moluccas passes from New-Guinea to NewZealand, conforming, though not strictly, to the outline of Australia. In Java alone there are said to be thirty-eight considerable volcanoes, some of which are twelve thousand feet high. These rarely emit lava, but they discharge quantities of sulphur and sulphurous vapors, and rivers of mud issue from them. The careful observer, Dr. Junghuhn, has with his Travels in Java presented us with an atlas, in which are interesting sketches of principal craters. Of these we may specify the Galung Gung, or Galongoon, which in 1822 was the scene of one of the most destructive eruptions of modern date.

Farther north, in the chain of the Andes, lic the lofty volcanoes of Bolivia and Upper Peru. The high land of Quito is described by Humboldt as being an enormous volcanic vault, and is bounded by two lines of burning mountains, amongst which are Sangay, Tunguragua, Cotopaxi, eighteen thousand seven hundred and twentyfive feet in hight; Antisana, no less than nineteen thousand feet above the sea level; also Pinchincha and Imbaruru. The underground fire breaks forth sometimes from one, and sometimes from another, of these openings, which are supposed to be separate volcanoes; and Humboldt states that, during his long stay at Quito, not a month passed in which there were not heard awful noises, with or without earthquakes, beneath their feet. In Central America, we find in Gaute mala, lying between the northern and southern continents, about forty volcanoes crowded together. All of these follow the various bends of the Cordilleras, in an almost unbroken row. One of the most terrific examples of volcanic activity, both in regard to the quantity of matter thrown up, and the magnitude of the accompanying phenomena, was an outburst of Cosequiva in Nicaragua, a volcanic hill only five hundred feet high, standing in a tongue of ground in the bay of Fonseca, on the Pacific coast. It began on the 20th of January, 1835, and lasted several days. The country round, over a space of fortythree leagues across, was wrapped in impenetrable darkness. The shore of the headland was pushed 800 feet out into the sea by the fall of ashes, and two islands of slag and cinders were thrown up in the bay. The fine dust was carried by the wind as far as Jamaica, and an English vessel was covered with the floating pumice at a distance of eight hundred miles out at sea.

The line of Mexican volcanoes is well known, and includes the lofty cone of Colima, and the ever-burning Popocata petl, seventeen thousand feet high. Another, of scarcely less hight, is Orizala. On a scale which equals or perhaps surpasses that of the Andes, there is a continuous line of volcanic action which commences on the north with the Aleutian Isles, in Russian-America, and extends

As the reader will feel more interest in descriptions of particular volcanoes, and their most important phenomena, we proceed to describe that famous mountain Etna, omitting to notice Vesuvius, as being better known and more frequently described, as well as inferior in magnitude.

The outline of this volcano forms an irregular circle of considerably more than one hundred miles in extent, a more or less prominent range of hights separating it at almost every point from the surrounding plain. An arched plateau, which marks the actual limits of the vol cano, rises above these hights on all sides towards the mountain, by an insensible inclination of two or three degrees. This mountain pedestal supports an elliptical cone, the sides of which form the lateral declivities of Etna, having a tolerably regular inclination of about seven or eight degrees. These lateral slopes abut on the central elevation, (the Mongibello of the Sicilians,) the highest part of which is terminated by a small inclined plane, (the Piano del Lago,) which is itself surrounded by the terminal cone, in which lies the great crater. Towards the east,