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of fire or water, that the movements produced by corresponding attractions are in no degree impeded. This general principle, supported by particular examples from the mineral kingdom, he applies to the veins both in primitive and secondary rocks; with one important difference, however, rendered necessary by his previous views, viz. that the veins in primitive rocks were formed by such attractions taking place during a state of igneous fusion; while those in transition and secondary rocks, owe their origin to combinations taking place in water, or rather in the heterogeneous mixture of water, earths, metals, &c. to which he attributes these later formations. Here it will be seen that M. Breislak again approaches the confines of the Wernerian doctrine; differing, however, in this, that he substitutes the idea of an elective attraction, contemporaneous with the formation of the rocks, for the tranquil precipitation of the Wernerian school, taking place in open fissures, which were subsequently filled with the fluid menstruum from above.
We have not room here to enter into any details on this question, which certainly is among the most interesting in Geology. Nor are we disposed, indeed, to comment with any severity on M. Breislak's theory of veins, though it does admit the operation of two such distinct causes, as fusion by fire and solution by water. It is perfectly possible, or even probable, that each of these may have had effect at different times in their formation; and while the subject is still so far embarrassed by difficul ties, it would be unwise to reject totally either the one or the other agency. In this point, however, the Huttonian theory has an obvious advantage, in explaining the origin of veins, which have the appearance of being filled from beneath; and, although the topic is one, upon which the Wernerians are accustomed to claim for themselves a superiority, we are persuaded that they have generalized their views further than the present state of our knowledge will permit, and have laid down laws, where the exceptions are too numerous to allow of their standing as such. In many points, we think that M. Breislak's views as to the combination and disposition of the materials of veins, are capable of being more plausibly applied to actual appearances.
The remainder of this chapter is occupied by considerationa as to the causes of the great inequalities on the earth's surface; its mountain chains, hills, basins, and vallies. We have already seen, that M. Breislak supposes these to be produced, in great part, by the escape and particular direction of gases, during the first consolidation of the globe. He now enters more at Jarge into this idea; and cites, in confirmation of it, the general direction of all the loftiest mountain chains from east to west;
which he conceives may have been owing to the direction the torrents of gas received from the rotatory motion of the earth on its axis. This hypothesis is a bold one; and we cannot help thinking that our author has generalized a little too much in its behalf, in the sketch he gives of the direction of mountain chains. We admit the greater number of the instances; but the exceptions are more numerous than he is willing to allow; especially if we come to the secondary chains, for the elevation of which it is necessary to account, as well as for that of the primitive. rocks. We may remark too that he gives an insufficient degree of importance to the changes produced by different agents on the surface of the globe, subsequently to the first period of consolidation. In commenting upon the opinions of Pallas, he again finds occasion to express his belief, that no elevation of rocks by heat has taken place since that time; except in the partial instances of volcanic agency. Upon this topic, we have not leisure for any further comments, and must hasten to the concluding chapters of the work.
The Seventh Chapter relates to Organic Fossil Remains; a subject which M. Breislak treats at considerable length; rightly conceiving it to be of the highest interest as a part of geological science. The arrangement and short sketch which he gives of these fossil remains, are well calculated, on the whole, for an elementary work. The labours of Cuvier, Blumenbach, Humboldt, and other scientific inquirers, have indeed laid an admirable foundation for research in this branch of geology; and we rejoice to find that the object is now generally prosecuted by mineralogists, with a zeal and accuracy proportioned to its importance. The discovery of marine fossils at the height of ten. or twelve thousand feet above the actual level of the sea;-the fact that a great proportion of these, especially those contained in the older limestones, are now unknown to us, except in the fossil state;-the evidence they afford, in certain places, of a repeated alternation having taken place of marine and fresh water depositions;-the discovery, among the newer rocks and alluvial strata, of innumerable bones of terrestrial and amphibious animals, many of them of vast size, and no longer known to exist on the earth;-all these circumstances give testimony to the value of such researches in reference to the natural history of the globe.
M. Breislak's theory, as to the origin of the marine fossils, depends upon what we may call the Neptunian part of his doctrine, though well aware how strenuously he would object to this name. The waters which deposited the transition and secondary strata, though heated and in an agitated state, were capable, he thinks, of supporting certain forms of animal life;
which increased in variety during the later periods of deposi tion. He considers that the strata, containing such fossil remains, were formed in their present situation; the waters, which at that time, had a corresponding level, having since retired to one much lower. The latter phenomenon he attributes to the falling in of the crust of the earth in various places; a passage being thus afforded into the great cavities in the interior, which may have been produced by the original unequal expansion of the ascending gases. This doctrine, in its main points, contains little that has not been suggested before; and we should only repeat old topics of discussion, in entering into any detailed argument on the subject.
The two concluding chapters of the work relate to Volcanoes, and to the Basaltic Rocks. Our author's intimate knowledge of the volcanic districts of Italy, gives great weight to all his remarks on the first of these subjects; and the chapter is certainly an interesting one; though there are several parts of it, particularly those developing his theoretical views, to which we find much reason to object. On the sketch which he gives of the different products of volcanoes, we have no remarks to make. His observations are taken in great part from Vesuvius and the Campi Phlegrei ; a district which affords a greater variety of products, and those of a more interesting nature, than any other volcanic region of equal extent that has hitherto been made known to us. The primitive fragments ejected from this mountain; the peculiar crystals, melanite, leucite, nepheline, &c. existing in its ancient lavas; and the extraordinary quantity of muriatic acid evolved, as well in the gaseous as in the combined form, are circumstances so striking in the history of volcanic phenomena, that we are not surprized to find M. Breislak attaching himself to this spot, with a peculiar and almost personal interest. Yet, notwithstanding this, and although he comes before us as a professed Plutonist, we are obliged to say, that we think his views too partial and limited as to the causes and extent of volcanic agency. His theory of causes, which was originally started many years ago, in application to Vesuvius alone, is very analogous to the Wernerian doctrine on the subject, and liable in great part to the same objections. He considers that the local combustion of petroleum or bituminous matters, aided occasionally by the access of the waters of the sea, may be the origin of all the phenomena; and, what he at first applied to Vesuvius only, he now extends, though with some hesitation, to other volcanic districts. An argument in support of this opinion is sought for in a vague reference to the number of bituminous springs existing in different parts of the world. It is
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scarcely necessary to remark how insufficient such proof is, and how inadequate the cause assigned, to explain the variety and magnitude of the effects in question.
We may extend further our objection to M. Breislak's manner of treating this subject; and remark, that he has not sufficiently pointed out those general and enlarged views of volcanic mineralogy, which are so important to the geological student. The living volcano, however magnificent and awful as a spectacle to the senses, is yet, in many respects, less interesting to the scientific observer, than those natural records of past convulsion, over which ages have slept in silence, and which receive no light from the history or traditions of man. The actual volcano, it is true, exhibits a great variety of products, some which cease to exist, when its action is at an end. But many of those products are merely superficial; and limit, rather than augment our knowledge, by concealing from ns those changes which are taking place beneath. In the ancient and extinct volcanic formations, the hand of time has done for us what no art could effect; and by throwing off the surface, and making its bold sections of these rocks, it displays their interior structure, shows us the effects of different modes of cooling, and different degrees of pressure, and teaches us the conditions which may influence crystallization in its various forms. The field of observation here, is of the most extensive kind; and much yet remains to be done in it. Even excluding all the disputed localities of basaltic rocks, we have in Europe numerous districts, where the former agency of fire is marked by the most unquestionable traces. This is the case in France, Germany, Hungary, Sardinia, and peculiarly in Italy; and we own that we are surprized, in this account, that M. Breislak should have entered so partially into the great general views which they suggest; more especially as, in the following chapter, he professes to consider basalt as a volcanic product. Our general knowledge of volcanoes, whether active or extinct, is rapidly increasing; and much has been recently added to it by the invaluable researches of Humboldt in the Audes and islands of the Atlantic; and by the observations of M'Kenzie in the northern volcanic region of Iceland.
M. Breislak notices, cursorily, the suggestion of Sir H. Davy, that volcanic phenomena may be owing to the admission of water or air to the metallic bases of the earths existing in the interior of the globe. He proposes two objections to this idea; -the first depending on the great lightness of these metallic bases;-the second having reference to the quantity of heat, which he thinks would be too small from this cause to account for the actual effects. To the latter, in particular, of these objections, we can by no means accede.
In one part of this chapter, we find M. Breislak speaking of volcanic appearances in the Orkney Islands and Hebrides; a statement which, in part at least, certainly requires correction. This is not the only instance in his work in which we discern inaccuracies relating to our own country. Some flagrant mistakes occur, in a table of the heights of mountains, which is prefixed to the first volume; of which one or two examples may suffice. The highest mountain in England is said to be Picco Ruivo, having an elevation of 5281 feet above the level of the sea. By a singular mistake, the estimate of Snowden is twice given; in the first instance at 3342, afterwards at 8555 feet; Whernside, or Wenside, as it is printed, is set down at 50 10 feet. Errors of this kind are not creditable to a catalogue, and throw suspicion on its general accuracy.
In the chapter on Basalt, with which our author concludes his work, he brings various arguments to prove its igneous origin; apparently without adverting to the inconsistency of this with some parts of his preceding theory. He has limited the causes and influence of volcanoes; and deprived himself of the aid of the central heat, by confining its action to a particular class of rocks, and to a certain period of time. In consequence of these difficulties, and probably from his having had himself few opportunities of examining basaltic rocks in ortu, his discussion of this topic is by no means complete or satisfactory. He scarcely seems aware of the extent and peculiarities of these rocks; of their occurrence in veins or dykes; of their singular relation to coal; and of their association with other rocks, and very remarkable position, in what Werner calls the newest
floetz trap formation. Considering the interest which these objects have excited among geologists, we are surprized that M. Breislak should pass over them so superficially, and with so little regard to their influence upon every part of the science.
ART. VIII. The History of the Church of Scotland, from the Establishment of the Reformation to the Revolution, illustrating a most interesting period of the Political History of Britain. By GEORGE COOK, D. D. Minister of Laurencekirk. 3 vol. 8vo. Edinburgh, 1815.
N spite of all the mockeries of their reverend historian, we cannot bring ourselves to believe that JACK is at all a worse fellow than either PETER or MARTIN. The two last, indeed, have contrived somehow to make a better figure in the world, and affect to look down on their less opulent brother. Yet per