and time had recently added to the art. His devotion to his duties, and his love to his pupils, supplied all; from the beginning he shewed himself worthy of his situation, and during the thirty years he filled it, the affection and gratitude of those whom he taught continually rewarded his labours. The gra titude of many others also was due to him, could he have reclaimed it from all those whom he has enriched.

In fact, if it be desired to know what effect a well arranged institution, however inconsiderable it may be, what a public professorship, for example, may produce in a great kingdom, let it be considered what our mines then were, and what they have since become. Our workings of iron and coal are quadrupled; the iron mines which have been opened near the Loire, in the coal district, and in the midst of fuel, will produce metal at the same price as in England. Antimony and manganese, which we formerly imported, we now export largely. Chrome, which was discovered by one of our chemists, is also now the very useful production of one of our mines. Already very fine tin has been extracted from the mines of the coast of Bretagne. Alum and vitriol, formerly unknown in France, are collected there in abundance. An immense deposit of rock-salt has lately been discovered in Lorraine, and there is every reason to believe that these operations will not stop there. It is not undoubtedly to a single individual, nor to the erection of a single chair, that all this good can be attributed; but it is not the less true, that this man and this chair gave the first impulse.

It was for his pupils that M. Duhamel composed his principal work, of which a volume appeared in 1787, under the title of Geometrie souterraine.

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It is well known that the metals, and especially the more precious metals, have not been distributed by nature in homogeneous and extended masses. Dispersed in small parcels among rocks, it is only by great labour that man has been able to become possessed of them. Nor have they anywhere been scattered at random. Their position, like all the other relations of natural objects to each other, is subjected to laws. It might be said that the oldest mountains have been broken or split to afford them asylums. Those immense fissures which traverse rocks in all directions,

look as if they had been subsequently filled with the foreign materials at the bases of the mountain, and it is in the intervals of these foreign rocks, in these veins, that the precious molecules, often of very varied composition, are deposited. From them the successive discoveries of chemistry have enabled us to extract the metals in their pure state.

The art of the miner consists in discovering principal veins, in following them, in finding them again when they are interrupted, in allowing none of the accessory veins which may intersect them to escape; lastly, in raising all the parts that may contain metal, and in raising none else. He must therefore know the general laws of the distribution of veins, of their inflections and intersections; and when he has wrought out a part, when he has perforated the mountain in every direction in which veins have presented themselves to him; when he has scooped out a second time this labyrinth, which seems to have existed since the original disruption of the rocks, and before the substances which fill up the fissures were deposited; he must be able at all times to find his way through those gloomy recesses, he must even retain an accurate knowledge of the galleries, of the veins which he has abandoned, that he may not be annoyed by the waters, on coming imprudently upon them again by a different route.

Such is the object of subterranean geometry; it finds out the direction of the veins toward the cardinal points, and their inclination to the horizon; it fixes the three dimensions of the works; it follows them, and verifies their progress by clear and distinct images. Its means are such as they might be in those narrow cavities, where the view extends only a few feet, and where the light of day does not penetrate. Some lamps, a compass, and an instrument to measure the inclination, are all that can be used. It cannot, like common geodesy, either connect its operations with those of astronomy, or establish great triangles, to rectify its small errors. It therefore requires particular methods, which supply by their accuracy of detail those grand means of rectification; and these methods must be such as men of the class who pass their melancholy lives in those depths, may comprehend and execute with sufficient accuracy.

These operations are what M. Duhamel teaches in his book.

It is not a work of an elevated order of geometry, nor one that had the pretension of offering new mathematical truths: it is a purely practical treatise, a sort of surveying of a particular kind, but which the art of mining could want, and which every miner would have been obliged to make out for himself, had not the author spared him the trouble. This work is at the present day the manual of all who practise the art of mining in France; and as if the light of improved science ought to reflect toward the focus from which it had issued, it has been translated into German, and is very generally diffused among the miners of that country.

In the subsequent part of his work, M. Duhamel intended to treat of the other processes of the art, of the various modes of digging, incasing, walling, ventilating, and drying mines, of transporting the ore, picking, washing, stamping, melting, and refining it. The police of mines, their administration, the questions of law which refer to them, and the regulations to which they are subjected in different countries, were equally to be explained. But the events which involved the country in confu-. sion a short time after the publication of his first volume, arrested the progress of the work, and we can form no idea of it excepting from the fragments which he has inserted in the Encyclopedie Methodique.

During these events, M. Duhamel himself was much distressed; but he acted as on all other occsions, he took precautions without complaining. At the first appearance of danger, he purchased some lands in America, and formed the resolution of carrying his talents to that country.

When on the point of embarking, he still granted some moments to the tears of his family: but in the few days which this delay occupied, the men who menaced every kind of merit were thrust down, and immediately the proposals of the government, which had been restored to some degree of moderation, fixed him anew in his country. After this period, he discharged the duties of professor and inspector-general of mines, and in the latter quality performed important missions, always with zeal, and always without ostentation. At length his age, and loss of strength, forced him in 1811 to retire. He was then 81 years old.

The remaining part of his life was passed in calm re

tirement among a beloved family. The pains of the gout alone sometimes interrupted his tranquillity, and caused him the greatest of his disappointments, by preventing him from going regularly, as he had been accustomed, to hear his fellow-members at the Academy, for there he was as constant as he was silent. In his family he was as modest and mild as in the world.

At length he slept the sleep of the just, on the 19th February 1816, aged somewhat less than 86 years. A son, one of his most distinguished pupils, and inspector-general of the mines, revives his name in the career on which he first entered, and in which this son has already made not less remarkable progress than his father.

Observations in Answer to a Memoir by Messrs Sedgwick and Murchison on the Austrian Alps*. By AMI BOue', M. D. F. G. S. M. W. S. &c. &c. Communicated by the Author. In the memoir of the two active members of the Geological Society of London, we were pleased to observe, that they had described and classified the various alpine deposites nearly in the order which we pointed out in our papers in the Edinburgh New Philosophical Journal for 1830, and in the Zeitschrift für Mineralogie von Leonhard, for 1829, and in the Journal de Geologie, Nos. I. & II. for 1830. Nevertheless, they have omitted some parts of the geological history of the Alps; or, at least, they hardly notice some of the prominent subdivisions of these formations, which certainly would not have escaped them had they allowed themselves sufficient time to take a more extensive view of that immense chain. As we are of opinion that the structure of the calcareous arenaceous chain of the Northern Alps presents peculiarities unknown on the southern side of the Alps, we could have wished that the authors in question had separated entirely the descriptions of each of these chains, because the intermixture of local details, sometimes from the one side, sometimes from the other side, are apt to deceive the reader, and induce him to believe that if a complete identity does

The memoir appeared in the Annals of Philosophy for August 1830.

not exist, yet that there reigns a great similarity between the succession of the southern and northern alpine deposites. It has been long known, that, in Carinthia, especially near to Bleiberg, true transition rocks, even with their characteristic fossil shells, make their appearance. Our authors have added new and interesting details to those already known, in regard to this isolated occurrence among the Alps, and excite the wish that these ancient rocks may be farther traced, with the view of ascertaining whether or not they do not actually extend under the secondary rocks, in the direction of Idria. Now, as these rocks are entirely unknown along the whole of the northern alpine chain, from the Mediterranean Sea to the Carpathians, and as they do not occur in the Italian Alps, it would have been better to have presented this fact as an isolated accident, rather than endeavour to join these rocks with other calcareous and arenaceous rocks, without, or nearly without, organic remains, which some may be disposed to call transition, while others will refer them to the secondary class. Besides, if these crystalline masses, containing encrinal beds, described as occurring on the northern side, are truly transition, certainly their characters differ from those of the rocks of Carinthia, containing shells. On the other hand, we see the term greywacke applied to rocks on the northern side of the Alps, which make a transition from the micaceous or chloritose quartzose rocks, to others with a still more arenaceous character. We confess that these last mentioned conglomerated masses cannot be compared with, or referred to, the greywacke of the Hartz or the south of Scotland, but to us appear mere varieties of quartzose talcose rocks, deposites also well known in Scotland, which are, in our opinion, less affected and altered by igneous agents than the other primary, but formerly arenaceous rocks.

After these general observations on our authors' mode of treating the subject, we shall now take the liberty of examining the divisions which they propose. They distinguish, in the Alps, 1. With all geologists, a central primary axis. 2. Crystalline rocks, with limestone beds, containing few organic remains, the system graduating into rocks agreeing with the ordinary transition type. 3. Red marl, sandstone, gypsum, &c. containing, in parts of their range, large subordinate masses of