junction took place 6m 35.3 sooner, or at 21h gm 26-8 apparent time, when the Sun's true place from the mean equinox by Mayer's tables was 7° 16° 17′ 13′′-3, or 7° 16° 17′ 8′′-5 if we take into account the correction to be made in the tables which the Greenwich observations make — 5′′ nearly. Hence the place of the node is found to be 1' 15° 58′ 56" 3. A LVIII. Geological Journey to Mount Ramazzo in the Appenines of Liguria; Description of this Mountain; Discovery of the true Variolite in its Bed; of Lime; of the Arragonite; and of Martial, Magnetic, Cupreous, and Arsenical Pyrites, in the Steatitic Rock; Manufacture of the Sulphate of Magnesia. By M. FAUJAS ST. FOND*. IN 1780, Messrs. de Saussure and Pictet visited the mountain Madona della Guardia, elevated 422 toises above the level of the sea, and of which mount Ramazzo forms a part. After having given an excellent lithological description of the first mountain, Saussure thus expresses himselft: "On ascending and descending the mountain della Guardia, we had a view to the westward of a mountain, from which we were separated by a very deep ravine, and from which we were informed that martial vitriol had been extracted; but I had no knowledge of the substance in which it was found. At the distance from which we saw this mountain, it seemed mixed with slate and ferruginous earths." It was this mountain, (known by the name of Mount Ramazzo,) thus neglected by Saussure, which principally occupied my attention for two reasons: in the first place, because I had been told that trenches were dug at the summit of this mountain, and that a manufacture of sulphate of magnesia had been established there: secondly, because, the steatitic and serpentine rocks of this mountain being. united to lime in certain points, I was anxious to visit this curiosity so seldom discovered. * From Annales du Muséum d'Histoire Naturelle, tome viii. p. 313. M. Maxi M. Maximilian Spinola of Genoa, who is skilled in several branches of natural history, M. Viviani a botanist, and my friend M. Marozari of Vicenza, an excellent mineralogist, were anxious to accompany me. We took our departure at six o'clock in the morning from Genoa: we went in a carriage to Cornigliani, where we visited M. Durazzo's rich collection in natural history: from thence we proceeded to Sestri, where M. Alberto Anseldo conducts a manufac tory of sulphate of magnesia with great spirit. This gentleman acted as our guide in the arduous excursion we were about to make our route lay through narrow by-ways, profound ravines, and we were obliged to climb from rock to rock, which were so flinty and slippery, that they required some experience in alpine travelling to surmount them. We left our carriages at Sestri, and immediately entered the bed of the river Charavagna on foot. We ascended this torrent for about an hour. Its bed is broad, and wholly covered with blocks of serpentine and other round stones; which shows that it is subject to dreadful torrents; but there is scarcely any water in it in dry seasons. The following are the remarks I made on ascending to a lime-kiln, which I shall speak of by and by. Notice upon the Stones in the Torrent of Charavagna. 1. Various pieces, larger or smaller, of a grayish steatitic rock, of a drier grain than that of the other steatites, of which I shall soon take notice. This rock has fissures or cracks filled with greenish crystallized epidote, similar to that of the alps at Oisan in the ci-devant Dauphiné. I am surprised how this rock escaped the attentive and vigilant eye of Saussure. It is probable, since he has not mentioned it, that the torrent of Charavagna was not then passable, or at least when he visited the mountain della Guardia. 2. Tender serpentine of a blackish green shaded with light green, and shining as if varnished, soft and even unctuous to the touch, radiating into white streaks, with a striated and undulous fracture, having a talcky appearance, and strongly obedient to the magnet. 3. Serpentine, soft, and analogous to that of No. 2, as to the the constituent parts; but its colour is of a clearer green: its surface is much more glossy than that of the preceding, and its fracture more gener lly undulated: but what particularly distinguishes this beautiful specimen, which is seven inches long by five broad, is, that it is not only very attractable by the magnet, but endowed with a strong polarity throughout its whole length; and it attracts keenly at one end, while it even repels with the other. 4. Serpentine of a deep green, with some shades of a clearer green, soft to the touch, but harder than the preceding, having one of its facets striated, and something like asbestos. 5. Another serpentine somewhat hard, of a greenish black, with small spots of a greenish white near to each other, and which seem to have a tendency to the parallelopipedon form, which gives to this variety of serpentine a false aspect of black and white antique porphyry. But what renders the latter remarkable, is, that it contains in its substa ce, as well as upon its external facets, a multitude of very brilliant small silvery scales of metalloidal appearance (diallage), the brilliancy of which is the more lively, as it shines upon a black ground. This serpentine is strongly attracted by the magnet. 6. Semi-hard serpentine, attractable, of a deep greenish black, with some laminae of métalloidal appearance like silver, and small layers more or less thin, but some of them a line in thickness, of a substance of the unctuous appearance of steatite; and its colour being olive-green, shining, and of an equal and rich tint, scems to be owing to chrome. 7. Semi-hard serpentine of a blueish-gray, with longitudinal compressed streaks, covered with a slight and transparent couch, or rather with a kind of varnish of a clear azure blue. We also discover in the fractures of this beautiful serpentine, some scales of a metalloid diallage, and of a silvery hue; it is attractable by the magnet. 8. Serpentine of a deep greenish-gray, semi-hard, feebly attractable, with small round globules, sometimes oblong, of a compact white or greenish substance, harder and more homogeneous than that of the stone which contains them, of of a steatitic aspect, and presenting, when we look at it through the microscope, very fine lineaments which unite about the centre of each globule. Here we have a true variolite, which ought not to be confounded with an amygdaloid. The specimen I have described, and which was confounded with the other stones I have mentioned in the bed of the Charavagna, is more remarkable from the globules being distinct, a little projecting and distinct from each other, as in the variolites of Durance, occupying one-third of the size of the specimen; they are also much nearer together, and seem to touch, and they are confounded afterwards; förming at the extremity of the piece but a single couch where the globules have disappeared, and where the same substance of which they are composed no longer affects the regular form. This stone fixed my attention, since it gave me reason to expect a variolite analogous to that of Durance, in a place where no person had met with it, or even suspected it to exist. As the globules, however, of the true variolite belong to a substance very like feldspar and fusible like it, and as I have neither met with compact feldspar, (petro-silex of the Germans,) nor feldspar under other forms; I think the round variolite which I found, was one of those stones transported in great revolutions of the earth, and out of its proper place. I made these reflections when advancing up the bed of the torrent; but I suddenly discovered a stony mass of a white or greenish hue, weighing more than thirty pounds, which, at first sight, awakened in my mind the idea of feldspar: it may be described as follows: 9. Compact stone, with fine paste, translucid upon the edges, soft to the touch, of a white slightly tinged with asparagus green, having the appearance of jade, breaking into scales rather lamellous than conchoidal, scratching glass strongly, and emitting some sparks when struck with steel; but it is not so hard as the jade. In the blow-pipe it bubup almost as soon as the fire touches it, and melts very soon into a yellowish transparent glass. On breaking this bles 2 stone, stone, we perceived some parts of a lively apple-green, arranged in small elongated laminæ, flat and of a silky lustre, owing to the diallage. I consider this stone as a true compact feldspar, mixed with a little steatitic serpentine, and with iridescence (diallage): it is this mixture which contributes, perhaps, to its great fusibility. I found another piece of it weighing more than twelve pounds. With the blow-pipe I made a comparative trial of the greenish-white globules of the variolite No. 8, which I found in the bed of the torrent, and they bubbled up and melted with the same facility as the stone I have described. Now, as the latter was of a large volume, and did not appear to come from any distance, for its angles were scarcely abraded, I presumed that it should abound in some parts of the neighbouring mountains, in the direction of the torrent which had received these fragments, and that it was perhaps found in a furrow, or mixed into the paste itself of some of the serpentines, which I thought I should find in its proper place. In fact, it was natural to think that the junction of the molecules of feldspar in globules, at the time of the formation of these mountains, might have given rise to variolites analogous to those known by the name of variolites of Durance; and thence I did not lose hopes of finding this kind of stone in the same rock which contributed to its formation. 10. Finally, the bed of the torrent, in proportion as I advanced, presented me with various fragments of a compact calcareous stone, hard and of a fine paste, susceptible of being polished, with some veins of calcareous spar which traversed it; I saw also some of the same spar adhering to a vein of white quartz. These calcareous stones found in a considerable number, beside the serpentine, magnesian, and feldsparry stones I have mentioned, left me also some hope of being able to observe the points of contact of the magnesian with the calcareous rock in a country quite free of wood, and torn up by torrents, presenting great hills and deep ravines. Reflecting in this manner, I advanced a little further, and in a deep recess |