ART. II.-1. Narrative of an Excursion to the Lake Amsanctus and to Mount Vultur in Apulia. By CHARLES DAUBENY, M. D. F. R. S., Professor of Chemistry and Botany. Oxford: 1835. pp. 50.

2. Report on the present state of our knowledge with respect to Mineral and Thermal Waters. By CHARLES DAUBENY, M. D. &c. Sixth Report of the British Association, London: 1837. pp. 98.

THE origin of Mineral and Thermal Waters, and the causes of the elevation of temperature in the latter, are so intimately associated with the general question respecting the internal temperature of the earth, and the geology of volcanoes, that we have been induced to notice these two publications of Dr. Daubeny in connexion. The one first named was a communication to the Ashmolean Society of Oxford, and has been published in a separate form; the second constitutes a part of the last volume of Reports of the British Association for the Advancement of Science. This last is one of the most valuable memoirs which have emanated from the annual meetings of that scientific body. May we not indulge the hope that the time is at hand when a similar association will be formed in this country? when enthusiasm will be elicited by the contact of congenial minds, and when, in the words of Professor Sedgwick, "the congregated philosophers of the land, throwing aside bad passion and party animosity, will, year by year, come to their philosophical Olympia, to witness a noble ceremonial, to meet in pacific combat, and share in the glorious privilege of pushing on the triumphal car of Truth."

A copy of Dr. Daubeny's narrative has but recently fallen into our hands, and we have reason to believe that it is much less generally known to our geologists, than many other descriptions of volcanic regions, of far inferior merit. It is a valuable and interesting contribution to geology, and one of the best models which can be recommended to the geological student or traveller. It describes, too, a tract of country celebrated in clas

* Address at the third meeting, 1833.

sic song, and has claims upon the attention of others besides mere geologists. General readers, who may anticipate nothing very attractive in a geological narrative, will find much in this, both interesting and instructive.

Since the appearance of Mr. Lyell's work, and Dr. Buckland's Treatise, the readers of geological works have, we suspect, greatly increased in numbers; and hundreds who, before, had probably little inclination to look into the narrative of a geological excursion, are now somewhat disappointed if a new book of travels does not contain some account of the geological structure of the country described. Notwithstanding this, there are many persons, and some we fear even of those who have acquired a taste for geology, who have yet to learn that a description of a volcanic region may afford new and interesting details. It is not difficult to understand how it happens that the appearance of a new work on fossils, or the description of the remains of some unknown animal, excites a more general interest than that of a work on volcanoes, or a memoir on some new volcanic product. We have, all of us, been made somewhat familiar from early life, with the many wonders of volcanoes; and the love of the marvellous is, from time to time, still gratified with partial accounts of eruptions and earthquakes. But it is only within a few years that we have heard much of fossil remains, and perceived the light they shed upon the former condition of our planet. In our days of boyhood we heard nothing of the beauty of a flying lizard, or of the symmetry of a Pterodactyle; the graceful attitudes of a Plesiosaurus had not been developed, and coprolites were unmentioned. We saw no tracks of a gigantic bird on the enduring rock, and heard more of the wooden skeleton of the mammoth than of his fossil bones. Touched with the Promethean torch of a Cuvier or a Buckland, the mountains teemed with life, and a strong and general interest was awakened; myriads of Trilobites, Dinotheriums. with jaws eighteen feet in length, started into being, and fossil geology takes precedence of volcanic. New light breaks upon us from the microscope of Ehrenberg, and we listen with wonder to the announcement that the very walls of our houses, the polished shaft and pointed obelisk, were once tenanted by microscopic myriads that each cubic inch of the stone contains millions of what were once animated beings, with powers and capacities of enjoyment, and all the complicated apparatus of life. We look upon the rocks and minerals about us with redoubled interest, and watch with tenfold wonder and delight the changeful opal,

and even the dull, unyielding flint, when we are told that they, too, are the monumental structures of tribes long since extinct.*

We would not, however, ascribe the interest that is felt in the promulgation of discoveries like these, altogether to their novelty; the perception of the light they afford in guiding us to a knowledge of the former condition and present structure of the planet upon which we dwell, is not confined to the geologist. No one can be more deeply impressed with the unquestionable value and importance of fossil geology than ourselves; but we think there is reason to apprehend the effect to which we have alluded, especially upon those who are but commencing their geological studies. Those who are proficients, will undoubtedly give its full value to the evidence afforded by volcanic, and by all other geological phenomena. Observations in volcanic regions, and the description of the products of volcanic action, by such travellers and geologists as the author of the narrative before us, while they will not fail to be duly appreciated by geologists, will gratify the curiosity even of those who expect nothing new or exciting in the department of geology to which they more particularly belong.

It is only from a careful study of the rocks and strata at the surface, that we can now derive evidence of the former existence and activity of volcanoes in various parts of the earth. We have no means of determining when these terrific agents first made their appearance, but must refer it to a very remote period, especially as regards the many extinct volcanoes, which must have ceased to burn before the commencement of history; for if they had been in action, we should find allusions to them in the most ancient writings which have come down to us. The earliest volcanic eruption upon record, if we admit the conjecture of Dr. Daubeny in his work on volcanoes, is that by which the cities of Sodom and Gomorrah were destroyed. This opinion may seem to be supported by the present aspect of the country, and strengthened by the observations of Burkhardt, who found an abundance of extinct volcanoes in the peninsula of Mount Sinai. According to this view, the date of the earliest volcanic eruption known in history, would be about 1960 years before the commencement of the Christian era. The earliest notice we

* Professor Ehrenberg of Berlin, has recently discovered that the polishing slate of Bilin, which forms a hill three hundred feet in height, is entirely made up of the fossil remains of microscopic infusory animals; - and still more recently, he has announced the discovery of vast numbers in the semiopal, in flints, and several other minerals. See Edinburgh Philosophical Journal.

find of an eruption of Vesuvius is in the 79th year of the Christian era, of which so minute an account has been given by the younger Pliny.* As to Etna, we can only infer from geological evidence that it was in action before the time of Homer, who is usually supposed to have flourished about 900 years before the Christian era, and as no allusion is made to it by him, that a long period of quiescence must have occurred before that time. The earliest mention of Etna is by Thucydides, who records three eruptions up to the date of the Peloponnesian war, which began in the year 431, B. C.

Some idea may be formed of the great influence of volcanoes upon the condition of our planet, when we reflect how they are distributed, and how numerous they are. Von Buch has enumerated no fewer than two hundred and twenty at present, or very lately, in activity. There are thirteen active volcanoes in Europe alone.

Many theories have been framed to explain the origin of volcanoes, and the cause of their eruptions, but there is none which can be deemed perfectly satisfactory. All the circumstances are opposed to the supposition that the phenomena are to be attributed to the combustion of beds of coal or sulphur, as some have imagined. Geologists are now more favorable to the ingenious views of Sir Humphrey Davy and Gay Lussac, respecting the access of water to the metallic bases, and the consequent chemical actions. It is true, there are great difficulties in adopting this theory, as for instance those arising from the specific gravity of the earth, which forbids us to admit that its interior can be composed of bodies whose specific gravities are so low; nor does it account for the gaseous matters which volcanoes exhale. Dr. Daubeny has with great ingenuity attempted to remove this last difficulty, by the observations he has made in Sicily and elsewhere, and by experiments on the spot upon the gaseous products themselves. He refers the muriatic acid given off, to the decomposition of the salt present in the water, the carbonic acid to carbonaceous matters that may have entered into combustion, or to the presence of carbonate of lime and magnesia, and the sulphuretted hydrogen and nitrogen, to the contact of salt water and air with the metallic bases. But we must refer our readers to Dr. Daubeny's work for the more important details, and chemical and other evidence, with which he has fortified his views.

Volcanoes have been well called the chimneys, or safety valves, of the globe; and where they do not exist, the elastic matters Epist. lib. vi.-epist. 16 & 20.

generated or evolved in the great subterranean laboratory, produce effects not less terrific than those of an actual eruption. Indeed it would seem that they not unfrequently give place, as remarked by our author, to a visitation of a much more destructive character," the most terrible effects being felt at a certain distance from the orifice, although the power of action is probably not far removed from the latter."

Whatever our theories may be in regard to the causes of volcanic action, the most vivid description or most perfect representation will give but a faint conception of the attending phenomena and effects. Who can paint an eruption of an Etna, a Vesuvius, or a Hecla? The phenomena are ever varied and changeful, as well as the most awful and grand, we can contemplate. We may be told that flames are vomited forth with dense volumes of smoke and vapor, rolling away and overspreading the earth for leagues. with thick darkness, partially and fitfully illuminated from time to time by the quick flashings of electrical light, while showers of red hot stones and ashes, with torrents of glowing lava, pour over the crater, and roll in fiery billows into the plains below, overwhelming and destroying every thing in their course;-we may picture to ourselves the frightened inhabitants hurrying in all directions with what few articles can be hastily snatched up, their path lighted up by the terrific eruptions, while the appalling thunders and deafening explosions peal along the suffocating atmosphere, and shake and rend the solid earth over which they are flying-but we shall still have only a faint conception of the scene. To most persons, phenomena of this kind may be the only ones of much interest, and they may imagine that as these mighty energies become exhausted, but little remains to awaken curiosity in the scoriæ, ruin, and desolation around. So far from this, much will be found both of interest and instruction, in the most indistinct traces of the former activity of volcanoes. Almost every step over a volcanic country adds something to our knowledge of the structure of the earth, or throws light upon the changes which it has undergone. We find mountains formed of marine deposits, which were once beneath the waters of the ocean, that have been raised up, and discern the remnants of those that have been engulfed; we find strata that once were horizontal and far below the soil, now presenting themselves to day, or broken up by huge dikes of trap and basalt, or traversed by enormous veins of porphyry, and granite. These, and many analogous appearances, almost innumerable, in every part of the earth, are rendered intelligible by the care