and made a discharge, with a noise resembling that of a discharge of cannon. A column of black and fuliginous smoke issued with great violence, and there was thrown up, with the rapidity of lightning, an enormous torrent of inflamed gaseous substances and burning stones, which fell back again like hail, for the most part into the gulf, but partly without it. I was overpowered with the grandeur of the spectacle, but I did not fail to observe, in particular, the column of flames which accompanied the explosion. It was the first time that it had fallen to my lot to witness such a phenomenon. The flame rose to the height of 4 or 5 yards, and then disappeared among the volumes of smoke, so that a person whose eye was on a level with the edge of the gulf could not have seen it. I mention this, because when volcanic explosions are viewed from a distance, and from places where the crater in action is not visible, it never happens that the flames are visible; whence it is that the existence of this phenomenon in volcanic actions has been denied. The flame which I observed was of a very decided violet-red colour. It was very obvious that the gas which produced it became inflamed by contact with the air, because it burned only on the circumference of the column, and in the interior was obscure, presenting, on a large scale, what may be seen in a lamp on a small one. After the explosion and fall of stones had terminated, another very remarkable phenomenon was perceived. Insulated flames, disposed in a very picturesque manner, remained in the bottom of the gulf, moved around the mouth, and flickered very slowly about the walls of the funnel; an appearance which might be compared, in some measure, si licet maxima comparare minimis, to the flame of alcohol burning in a crucible. The beautiful violet colour of the flame was then easily distinguished; a faint smell of hydrogen gas accompanied these phenomena. I continued for a quarter of an hour gazing on this enchanting spectacle, and during that time I saw five explosions always accompanied by the same appearances; I would have remained longer in the same spot, had not the last of these explosions, which was much more violent than any of the preceding, compelled us hastily to retire.

I have had no opportunity, since the above noticed occasion, of observing the great opening of a volcano in a state of explosion; but I have noticed the existence of flames in circumstances nearly similar.

In the month of June, the following year, Vesuvius was in a state of eruption; on the evening of the 7th I paid a visit to the crater. The interior cone was throwing up stones with such violence that it was impossible to approach it. A current of lava was spouting out through a fissure at its base. Quite near to me, there was an elevation of a longitudinal form, which bore eight small cones, or rather eight large tubes of lava, open at the summit, and throwing out gas and steam with a whistling noise that was quite deafening, and which might be compared to that caused by opening the valves of a high-pressure steam-engine. Favoured by the darkness, we saw that their actions were accompanied

with beautiful conical flames, which issued from the tubes with a violence which might be in some measure compared to a flame increased in intensity by a blow-pipe. The length of these flames was from 3 to 5 inches, and their diameter at the base about an inch and a half; they burnt with a beautiful greenish colour, like alcohol holding boracic acid in solution: such a colour would very likely be produced by the chloride of copper accompanying the gaseous substances. The smoke which escaped from the openings in the cones had an intolerable smell of muriatic acid; sulphureted hydrogen gas was not perceptible. This was the second time that I observed flames in the crater of Vesuvius, and I saw them in company with my esteemed friend M. Ravergie of Paris, who was my companion in this expedition.

I saw very beautiful flames from Vesuvius, for the third time, during the great eruption in August 1834. An opening was formed in the volcano at its eastern base, and a great current of lava was thrown out, which spread over the fertile lands of Ottajano. In the place where the lava issued, two elevations were formed, which supported twelve small cones, kinds of hornitos, all of which were in great activity, and produced noisy explosions. One of these cones, which appeared the most active, and which I could approach near, notwithstanding the smoke it spread on all sides, was emitting by its opening, besides quantities of stones, a bright flame of a reddish-white colour, which came forth with great violence, and rose to the height of 3 yards. The jet was continuous, like the flame from a high furnace heated by bellows. The smoke was charged with muriatic acid, and, in a few moments, it enveloped Professor Tosone of Milan and myself in such a manner that we were nearly suffocated.

But my friend, M.

I never had the good fortune to observe flames in Vesuvius in so distinct a manner as on these three occasions. I have never seen them on the surface of currents of lava far from their source. Maravigna, assures me, that he observed them on a current from Etna, during the eruption of 1819.

According to all that I have said, my belief is, that volcanic explosions are constantly accompanied with flames. So convinced am I of this truth, in regard to Vesuvius, that I would engage to point them out during any eruption, provided the circumstances were at all favourable. I again repeat, that if the existence of this phenomenon has been denied, it is owing to the great difficulty of observing explosions very near at hand; and when they are observed far from the aperture in action, as is usually the case, the flames are either concealed by the walls of scoria which surround them, or, if they rise, they disappear among the smoke and jets of stones.

The phenomenon of which I speak is not an accidental one in the great actions of volcanoes. It is only necessary to see it once to be convinced that it is intimately connected with the cause of these actions. It may be said that flames are the most remarkable circumstance in volcanic

explosions, as the latter are the most essential phenomena of eruptions we may perceive in them the most direct external manifestation of the origin of the internal commotion. It is for this reason that I consider my observations on the flames of Vesuvius as tending to assist in explaining the cause of volcanic phenomena.

Reviewing what has been stated, I think the following conclusions may be drawn from it :

1. Flames never appear in Vesuvius but when the volcanic action is energetic, and is accompanied with a development of gaseous substances in a state of great tension; they do not appear when the actions are feeble.

2. Their appearance always accompanies explosions from the principal mouth; only they cannot be observed but in favourable circumstances. 3. They likewise shew themselves in the small cones in action, which are formed in the interior of the crater, or at the foot of the volcano.

4. Finally, they are not visible except in the openings which are directly in communication with the volcanic fire, and never on the moving lavas which are at a distance from their source.

After this exposition, it is natural to enquire, what is the gas which produces these flames in Vesuvius ?*

Dependence of the Geographical Relations of Countries and Nations, on the extent and situation of Forests.

THE rapid progress of all the material interests of nations during the general peace, which has liberated the German tribes, in particular, from the foreign yoke imposed on them from the West, was not without considerable influence upon the theoretical and practical turn of those sciences, which principally forward those interests, and are essential to their promotion. Among these sciences, Geography, which has for its object all the measurable, physical and political relations of the earth, holds no trifling, but rather a highly important place, because it offers various scientific, historical, and philosophical data, and considers them in their imposing details, in reference to the character of countries, nations, and empires. Its object is, harmoniously to connect the endless variety of the phenomena of our globe, to subordinate the accidental to what is regulated by laws, to establish an uni

* From Comptes Rendus, 1843, No. 17, p. 889.

versal connection between the individual facts, and to investigate the general laws, those tokens of a Divine order of things.

Its object does not consist in producing a long list of isolated facts without meaning, but it consists in representing to the senses the influence of Nature upon nations, and mankind in general; in showing the intimate connection between the general aspect of the earth and the particular physical character of the countries on the one hand, with the progress of civilization on the other, by means of giving an accurate description of the contrasts between highland and lowland countries, to be regarded as a basis and distinguishing characteristic; as also by discussing the method, according to which the knowledge of the physical character, and of the elevation or depression of countries, establishes a system of significant relations between all the different portions of continents, and gives precision and certainty to delineations and political relations. By considering the subject-matter of geography under this point of view, the method underwent a material change; the former was raised to the rank of a science, and an almost universal interest excited in its favour; for geography is now taught, not merely for the sake of its usefulness, but principally for the sake of moral and intellectual improvement. The want of a solid system of teaching geography is more and more generally felt, both as regards deeper scientific pursuits, and as regards the acquisition of knowledge bearing upon the various branches of industry; there is also a constant increase in the accumulation of geographical data, which, in spite of the great progress geography has experienced, in its new character of a science (thanks to the distinguished labours of Professor Ritter), can scarcely be mastered, whilst the interest taken in the drawing of comparisons becomes daily stronger. Abstracting entirely from mathematical geography, that is, from all the measurable terrestrial relations, and keeping in view the physical relations only, there still remains an extraordinary quantity of matter for scientific investigations, which forms a basis for political elements, and furnishes the most certain and positive evidence of the intimate connection between the earth and the human

race, and of the absolute dependence of the various stages of civilization, which nations and empires are destined to pass, upon the physical characters of countries.

These physical relations are considered in reference to Continents, taken in their whole extent, viz., they embrace stereography, hydrography, and atmospherography; the distribution of products; even man himself, according to his natural elements, composed of, or resulting from, the varieties of races, and the influence of the earth upon mankind in general; finally, they embrace the changes which have occurred on our globe, together with the operating causes. Not losing sight of the principle, that nature exerts a powerful influence on nations, and mankind in general, and that the greater or smaller progress of all the geographical relations of nations depends on the development and amelioration of the physical condition of continents or countries, it is easy to perceive, that what is termed political geography entirely rests upon physical geography; for, in the first place, it has to explain the physical character of the country, its situation, elevation, and depression, as well as its condition and degree of cultivation; and, in the second place, it has to inquire into the intellectual, religious, economical, and political relations of the population, as also to give an estimate of the amount and density of the latter.

A general survey of this department of political geography shows, to the attentive philosopher, that all the relations just enumerated, are closely connected with the physical development of a country. On searching for the conditions, means, and causes of this natural development, one discovers them in the presence or absence of forests, or in their extent corresponding to the other relations; for the physical history of every country, from the remotest periods down to the present, furnishes innumerable arguments in support of the truth, that a moderate extent of forests, especially on mountains, and elevated ground, where tillage is impracticable, promotes in a high degree agriculture, trades, manufactures, and other enterprises for increasing production; also commerce, and all the interests of individuals, as well as of entire nations.