the process; and finding on an examination of the native products, all the proofs necessary to substantiate it, we accede to the demonstration. But in the transition of bardiglione, now in question, there is no decomposition indicated, no loss of any principle, no replacing of one principle by another; it is simply the fortuitous introduction of a new principle, which, as far as it appears, has but an extremely weak affinity for the molecule of the substance, which however it must divide into its constituent molecules, since it has to form with them integrand molecules of a different figure belonging to a new compound. Of this we can form no idea; and as nature, when consulted respecting the facts, offers no foundation, on which we can in reality establish the existence of such a transition, we cannot adopt it. If this transition were admitted, it would put an end to all constancy in the nature of mineral substances. The moment they were in contact with any principle whatever, whether this principle could pass as easily as water, or through its intervention be received into their substance, changes would take place, and the large assemblages of matter would be in a continual state of transformation.
In the mountains of La Grande Chartreuse I have observed a calcareous stone including cylindrical nodules, three or four inches or more in length, one half of which was in the state of brownish-red oxide of iron, while the other was compact black oxide of manganese; and I have seen specimens of this stone, containing a great number of such nodules crossing them from one side to the other. I have a cylindrical Entrochus about eight lines in diameter, and which, before I had occasion to break it, was two inches and a half long; the exact half of it, supposing it to be cut in the direction of its axis throughout its whole length, is a grey lamellar carbonate of lime, while the other half is a deep violet granular fluate of lime: this Entrochus came from Derbyshire. Those fine specimens
