glorious example. Criticism has the great advantage of exciting emulation, of drawing the attention of competent judges to experiments and theories, which would spring up only to perish, if they were not resisted. Who does not know, and is not ready to confess, that a serious examination, even though hostile and severe, is much preferable to the subject being allowed to pass over in silence?

But in order to criticise the works of others, and form a judicious and intelligent estimate of them, a union of qualities is required, which unfortunately are rarely met with in a single individual, but which Berzelius possessed in a high degree. We do not indeed pretend that this illustrious chemist was without faults, that he was a diamond without a flaw; Alas! No! he was a man, and as such, liable to error. But we maintain against all, that few learned men have united in the same degree, eminent and indisputable merit, a theoretical and practical superiority universally recognised, a profound knowledge of all that has been done; and, finally, the consciousness that he had a duty to fulfil, a mission to execute.

Yes, we regret Berzelius, for we can never forget the eminent services he rendered every day to science, and we lament to see the threshold of the temple henceforth without a guardian, admitting the entrance of every crude theory, and every vagary of the imagination. Chemistry, in our day, is taking a wrong direction, and the eye of the philosopher observes it with sorrow again entering upon the dark path from which the past century had scarcely extricated it. Chancellor Bacon, the mystic Paracelsus, and before them, our countryman Van Helmont, had however pointed out the superiority of experiments to preconceived theories, and the worthlessness of systems formed before experiment! In the present day, there is no unity in the work; some seek for a new classification, or a new system; they imagine that they find a system while seeking for it, and giving, according to the expression of a modern author (Kiréevsky Historie des legislateurs chimistes), a new aspect to the great work; they assume altogether the character of the ancient alchemists. Others endeavour to teach organic chemistry; they mystify

it, they do nothing that is of any use. Ought not a new Berzelius to seize the sceptre fallen from the lifeless hands of the illustrious critic, in order to recall these fruitless labourers to order, and shew them by his example, how science should be promoted?

In his personal relations Berzelius was simple and plain, without those pretensions which, arising from an exaggerated notion of their own importance, sometimes diminish the pleasure which ought to be derived from the company of men eminent in science. He rose at an early hour, and no visitor ever found him unoccupied. No one, whoever he might be, could ever complain of his reception. He knew the full value of time, and he endeavoured to make others know it also. During a career of seventy years, forty-four of which were passed in the same city, engaged without intermission in difficult, and sometimes painful undertakings, Berzelius knew how to preserve the attachment of his pupils, the friendship of his colleagues, the esteem of his sovereign, and the respect of all. Many of the most distinguished chemists of the age resorted to his laboratory, such as Mitscherlich, Gmelin, Henri, and Gustavus Rose, Woehler, Magnus, Arfwedson, Mosander, &c. All entertained a boundless respect for their master, for they regarded him as the primary cause of their success in science, as the spirit which formed their minds, and gave a proper direction to their studies.

Perhaps we shall be accused of having attempted an eloge of Berzelius; but our ambition has not been so aspiring. While defending this great man from the unjust reproaches with which he has been assailed, it has been our desire, on this solemn occasion, to call to mind his principal titles to fame. In describing the course of a life as lengthened as it was well employed, we have endeavoured to shew to all young chemists, that present tendencies may lead them astray, and how they may succeed in laying the foundation of an imperishable reputation, and a glorious name; how, in order to advance the experimental sciences, it is necessary to sustain natural genius by a steadfast perseverance, and a continual labour, which nothing should discourage.

On the Relations of Trap-Rocks with the Ores of Copper and Iron, and the similarity of the Schalstein of Dillenburg, the Blatterstein of the Harz, and the Gabbro of Tuscany.

(Continued from vol. xlvi., p. 306.)

I. The Relations of Trap-Rocks with Ores of Copper and Iron.

This extension of geognostic relations between repositories exclusively cupriferous and the trap rocks, gives some importance to a more detailed examination than we have had occasion to make, of the copper ores and traps of Dillenburg. We find, indeed, between the veins of this country characterised by copper pyrites and the greenstones, which form the principal features of the accidents and composition of the country, relations different from those we have pointed out in Tuscany, and which add some facts to the relations which, in so many instances, render copper ores subordinate to trap-rocks.

If we examine the environs of Dillenburg on the geological map of Germany, we will perceive that this country, lying towards the northern border of Nassau, forms an islet in the transition mass remarkable for its peculiar composition. Narrow zones, composed of alternations of slates and limestones, supposed to be Devonian, run from the south-west to north-east, following the general direction of the great zone of anthraxiferous limestones, which traverse Belgium and Rhenish Prussia, more to the north. These slates and Devonian limestones lie above the greywackes and Silurian slates of the mass, interrupted by strongly-developed traprocks, arranged in zones following the same direction. A second group of the same rocks, affecting the same disposition, is found a little more to the south from Limburg to Weilburg and Braunfels.

II. Relations of the Schalstein of Dillenburg, the Blatterstein of the Harz, and the Gabro of Tuscany.

The trap-rocks of Dillenburg cover a considerable surface (8 to 10 square leagues), without, however, being very conspi

cuous, because their blunted forms present only gentle slopes covered by an active vegetation. But they can be studied in numerous excavations, where we perceive the massive structure of the greenstones, a structure often globular, so as to present mammelated surfaces.

The tissue of these rocks is generally homogeneous and compact; their colours deep, often ochreous on the surface, but greenish in the fractures which reach the unaltered rock. These appearances, moreover, are subject to variations sufficiently indicated by the multitude of names applied to them, such as greenstone, traps, variolites, amphibolites, diorites, &c. If we look for analogous formations, these rocks cannot be better compared than with those, which, in fact, bear the same names in the group of the Harz mountains.

If we study attentively some of the principal trap masses, we observe that the central part is pretty constant in its characters; it is a green rock, homogeneous and compact, the true type of greenstone. The variations which have caused so many different names to be applied to it, occur principally towards the exterior zones; a condition which we have pointed out in the serpentine masses of Tuscany, and which likewise exists in the greenstone of the Harz. If we examine the true rocks of contact, we shall find them exhibiting characters still more complex, but which always remind us of some of those of the trap type.

These rocks of contact are designated at Nassau by the general denomination of schalstein.

It is very difficult to define schalstein. It is most frequently a compact and lithoid rock, green or reddish, much rent, especially in the general direction of the stratification; some varieties are even slaty, others are brecciform and massive. The red colour of schalstein sometimes becomes very deep, and it contains, occasionally, conformable beds of red peroxide of iron. Lastly, the variolitic amygdaloids, with calcareous nodules, also form part of the schalstein, and develop themselves more especially in the parts of the locality where the Devonian limestones exist.

The schalstein has long attracted the attention of those who have studied the rocks of Nassau. Becher, Walchner, VOL. XLVII. NO. XCII.-JULY 1849.

B

Stifft, Leonardt, de Dechen, &c., have described the characters of these rocks, and distinguished from the schalstein, properly so called, 1st, The kalktrap, which are compact rocks, homogeneous, green or red, characterised by a mixture of limestone with the elements of the greenstone; 2d, The mandelstein, which are nothing else than our amygdaloids, rocks of contact which connect the preceding with the greenstone.

M. Oppermann published, in 1836, a treatise on the schalstein and kalktrap, in which he reviews all the opinions previously published. These rocks, he says, are situate at the contact of the greenstone with the greywackes, slates, or limestones, in such a manner that, according to the localities, they may be studied in very different media, whose characters they reflect. M. Becher has studied the schalstein principally in the limestone formation, Walchner in the formation of clay-slate, and Stifft in the greenstone; so that each of them has characterised these rocks by the predominance of lime, clay, or magnesia.

All these observers appear to agree in regarding the schalstein, kalktrap, and mandelstein, as rocks subordinate to greenstone, forming the passage between the crystalline rocks and the argillaceous or limestone rocks. Some of them, however, have separated the argillaceous schalstein, which they consider as a normal rock subordinate to the slaty rocks; while the kalktrap and the mandelstein cannot be supposed to have any other origin than the greenstone. With regard to ourselves, we consider all these varieties as metamorphic rocks.

If we set aside the amygdaloids, the schalstein exhibits the greater part of the characters assigned to the green and red gabbro of Italy. By the amygdaloids and subordinate beds of oligistic iron, they become confounded with the blatterstein of the Harz.

All the considerations we have brought forward to shew that the gabbro is stratified, may be applied to the schalstein and blatterstein, for these three types of rocks present remarkable resemblances in the conditions of their positions. All the three are found towards the outskirts of the