borough, in the state of Maine, described in vol. i. page 386 of this Journal, were noticed. Mr Brayley pointed out a remarkable affinity, in mineralogical characters, subsisting between these meteorites, and those which fell respectively, at Loutolox in Finland, in 1822, at Jonzac, in France, in 1819, and at Juvenas, in the same country, in 1821. This affinity partly consists in the strong resemblance which they all bear to certain products of volcanoes; whilst the meteorites of several other descents connect them, by a gradual transition, with those whose characters are more peculiar. From these and other circumstances, in conjuction with that of the frequent presence of olivine in meteorites, the author infers, that the agencies which give rise to volcanic phenomena, whatever these may be, and however exerted in this case, are probably concerned in the production of igneous meteors, and the bodies which descend from them.

Silicon.-Professor Berzelius has succeeded in obtaining the base of silica in an insulated state. The method consists in acting by potassium on dry silicated fluate of potash, by which means a mixture of various substances is obtained, which yields hydroguret of silicon by being well washed with water; and when that substance is heated in a crucible the hydrogen is burned off, and the silicon obtained pure. Professor Berzelius has given the results of various experiments upon this substance; among which are the following. It is obtained in various states of aggregation, and its combustibility varies accordingly, it much resembling carbon in this respect; as usually obtained, it is combustible when ignited in atmospheric air, and in oxygen gas; but in its densest state, it may become incandescent in the air without burning. It is very difficult to effect its complete combustion; 200 parts of silicon unite to 208 of oxygen to become silica. It will not burn when heated with nitre, but is brought into combustion by carbonate of potash; a curious circumstance, which the author attributes to certain relations of affinities. Silicon burns when ignited in chlorine, forming with it a transparent colourless fluid, having the smell of cyanogen. It is combustible in vapour of sulphur, producing a grey sulphuret, but cannot in this case be completely burned.-Ann. Philos., June.]

New Minerals.-Mr Brooke has lately described two new minerals; to one he has given the name Childrenite, in honour of Mr Children, who has contributed so much to mineralogical chemistry; the other he has called Somervillite. Childrenite was met with in Devonshire, and was at first supposed to be carbonate of iron, but Dr Wollaston determined that it was

a phosphate of alumina and iron. The primary form of the crystals is, according to Mr Brooke, a right rhombic prism. The crystals scratch glass, and their colour is wine yellow, resembling some varieties of sulphate of barytes.

Somervillite was sent, among other Vesuvian minerals, to Mr Brooke, by Dr Somerville; the primary form of the crystals is a right square prism; colour a very pale dull yellow; they occur in cavities with crystallized black mica. This substance might at first view be mistaken for idocrase; but it is much softer, the cleavage parallel to the terminal planes much more distinct, and the cross fracture more glossy. Mr Children has compared the characters of this mineral under the blow pipe with those of idocrase. When exposed alone in the forceps, it slightly decrepitates, which idocrase does not, and fuses, with greater difficulty than idocrase, into a greyish glass, the globule from idocrase being greenish. With borax, in the reducing flame, idocrase produces a light-green, and this a colourless glass.

Mr Brooke has also ascertained that the mineral called kupferschaum by the Germans, is the same as the fibrous or flaky bright-green substance found at Matlock, and is a carbonate of copper and zinc.

Iodine in Mineral Waters.-M. Angelina has discovered iodine in the waters of Sales, in Piedmont; and M. Krüger, of Rostoch, has detected it in the mother liquor of the saline springs of Sülzer, in Mecklenburgh-Schwerin. M. Fuchs has also found the same substance in the mother water of the Sal Gem of Halle, in the Tyrol. It appears, however, that as yet the iodine has not really been separated from their mother liquors, but its presence has been ascertained by the blue colour given to starch dissolved in nitric acid, and there appears to be no doubts in the minds of the experimenters, on the reality of its presence.-[Gior. de Fisica.]

South America.-M. Humboldt communicated to the Academy of Sciences at its last sitting, some very interesting observations made by Messrs Boussingault and Reveno. These gentlemen have analyzed an aërolite, weighing seve ral quintals, which they found in the mountains of Santa Rosa, to the northeast of Santa-Fe-de-Begota. They say, according to letters from Antioquia, that a mass of native gold has lately been found, weighing more than one-hundred and ninety pounds. They have proved the presence of both sulphuric and muriatic acids, in the waters of a small river which runs from the volcano of Paracé, near Popayan,and which is called by the inhabitants Vinegar river.-[Philos. Mag.]

Observations on the Lakes of Canada, &c.-In a memoir read at a meeting of the Geological Society of London, April 23d, by Lieutenant Portlock, R. E. the author described the va rious nature of the shore, of Lakes Huron, Michigan, Erie, and the other lakes of Canada, and annexed a plan, in which a tabular view was presented of the comparative level of these lakes and their communications with each other. At the falls of Niagara, he observes, the upper stratum is a firm compact limestone, resting on strata of a very schistose nature. It is not by erosion of the surface, that the falls are made to recede, but the waters after falling one-hundred and fifty feet, strike the bottom, and are reduced to foam; they are then driven up into the air far above the rock whence they had descended; this penetrating foam acts on the lower argillaceous strata, till the overhanging rock is undermined. Lieutenant Portlock remarks, that there has been a gradual fall in the level of the lakes at Canada.-[Ann. Philos.]

New Locality of Apatite. I have lately found this mineral in considerable abundance at Billerica, in Massachusetts. It occurs about two miles beyond the meeting-house, on the western bank of Concord river, in a coarse granite, the felspar of which is of a beautiful flesh red colour, and in concretions of very great size. This granite appears to be a vein, and the apatite, which is the conchoidal variety, the asparagusstone, is in distinct crystals, which are six-sided prisms truncated on the lateral edges. It is probable that this will be found to be the richest locality of this beautiful mineral, as yet discovered in the United States.

Arsenical iron and Galena have been met with, in small quantity, in veins of quartz traversing granite and gneiss, at Dunstable on the river Nashua. Tourmalin and garnets occur at both these localities. J. W. W.

THE

Boston Journal

OF

PHILOSOPHY AND THE ARTS.

ART. I.-On Rock Formations. By BARON ALEXANDER HUMBOLDT. [Edin. Jour.]

[Concluded from page 21.]

FROM that scepticism which would deny the existence of any kind of regular order in the position of rocks, it is proper to distinguish an opinion which has sometimes found supporters among experienced observers. According to this opinion, the formations of gneiss-granite, of greywacke, of alpine limestone, and of chalk, which have a uniform superposition in different countries, do not very well correspond among themselves as to the age of the homonymous elements of each series. It is thought that a secondary rock may have been formed on one spot of the globe, while transition rocks did not yet exist on another spot. In this supposition, no allusion is is had to those granitic rocks which are found lying above limestone containing orthoceratites, and which are consequently newer than the primitive rocks. It is a fact generally admitted at this day, that formations of analogous composition have been repeatedly deposited at epochs far removed from each other. The doubt which we are now considering, (though we do not partake in it), bears on a point much less clearly established,the ascertaining whether certain mica-slate rocks, evidently situated in the midst of a country of primitive rocks, and

placed below those in which the vestiges of organic life begin to appear, are newer than the secondary rocks of another country. I confess, that, in the part of the globe which I have had an opportunity of examining, I have not seen any thing that might tend to confirm this opinion. Granular syenitic rocks repeated twice, perhaps even three times, in primitive intermediary (and secondary) deposits, are analogous phenomena with which we have become acquainted within these fifteen years. This disagreement in regard to age of great homonymous formations, does not by any means seem to me to be proved as yet by direct observations, made upon the contact of superimposed formations. The chalk or Jura limestone may, on one hand, immediately cover primitive granite, and, on the other, be separated from it by numerous secondary and transition rocks: these very common facts demonstrate only the abstraction, the absence, or non-development of several intermediary members of the geognostical series. The greywacke may, on one hand, dip beneath a felspar rock, or rock of which felspar forms a principal constituent; for example, beneath transition granite or zircon syenite; and, on the other hand, be superimposed upon the black limestone containing madrepores; but this position shows only the intercolation of a bed of greywacke between felspar rocks. Since the minute investigation of fossil organic bodies has, through the important labours of Messrs Cuvier and Brongniart, diffused a new life as it were in the study of the tertiary formations, the discovery of the same fossils in analogous beds of very distant countries, has rendered the isochronism of very generally extended formations still more probable.

It is this isochronism alone, this admirable order of succession, which seems given to man to investigate with some degree of certainty. The attempts which theological geologists have made to subject the periods to absolute measurements of time, and to connect the chronology of ancient cosmogonic narrations with the observations of nature, could not possibly have been productive of satisfactory results. "It has been more than once," says M. Ramond, in a discourse replete with philosophical views, "thought that a supplement to our short annals might be found in the monuments of Nature. There is, however, enough of historical ages, to let us see that the succession of physical and moral events, is not regulated by the uniform progress of time, and could not consequently give it measure. We see behind us a series of creations and destructions, by means of the strata of which the crust of the earth is composed. They give rise to the idea of so many