Petralogy: A Treatise on RocksWhite, Cochrane & Company, 1811 - Petrology |
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Page vii
... contain are different from those ever found in lava . The experiments of Sir James Hall , which had been thought to establish the volcanic nature of basalt , he considered as defective . In basalt , hornblende and felspar are distinctly ...
... contain are different from those ever found in lava . The experiments of Sir James Hall , which had been thought to establish the volcanic nature of basalt , he considered as defective . In basalt , hornblende and felspar are distinctly ...
Page 16
... contains plates of splendid talc , varying in size from half an inch to many feet in diameter . It chiefly occurs in the Ura- lian mountains , whence talc has sometimes been called Muscovy glass . NOME XIII . FELSPAR , FIBROUS SIDERITE ...
... contains plates of splendid talc , varying in size from half an inch to many feet in diameter . It chiefly occurs in the Ura- lian mountains , whence talc has sometimes been called Muscovy glass . NOME XIII . FELSPAR , FIBROUS SIDERITE ...
Page 18
... contain very little mica , but abundant felspar , yellow or reddish , and quartz , of which the aspect sometimes approaches that of the chalcedony . The pyrites is interlaced in a re- markable manner , being in plates nearly regu- lar ...
... contain very little mica , but abundant felspar , yellow or reddish , and quartz , of which the aspect sometimes approaches that of the chalcedony . The pyrites is interlaced in a re- markable manner , being in plates nearly regu- lar ...
Page 31
... contains - mag- nesia 50 , silex 38 , oxyd of iron 9. This is also the chrysolite analysed by Klaproth . 4. Olivine , called by some volcanic chrysolite , ' has also been analysed by Klaproth , and though ' it contained rather more ...
... contains - mag- nesia 50 , silex 38 , oxyd of iron 9. This is also the chrysolite analysed by Klaproth . 4. Olivine , called by some volcanic chrysolite , ' has also been analysed by Klaproth , and though ' it contained rather more ...
Page 32
... contains large crystals of siderite , some- times an inch and a half in length , of a black or very dark green colour , but numerous other crystals of a lighter green , which every candid observer would allow to be the same substance ...
... contains large crystals of siderite , some- times an inch and a half in length , of a black or very dark green colour , but numerous other crystals of a lighter green , which every candid observer would allow to be the same substance ...
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Common terms and phrases
ancient appearance argillaceous barytes basalt basaltin base beautiful beds bricia brown calcareous called cement chalcedony chiefly chrysolite clay colour common compact lava composed contains crater crystallisation crystals decomposed decomposition Dolomieu drosses earth ejected eruption Etna feet felsite felspar fire flame flint fracture fragments garnet glass globules gneiss grains granite green grey heat height hill hornblende HYPONOME inches iron jasper kind Kirwan layers leucite lime limestone marble masses mica Micronome miles mineralogy mountain naptha nature nitrous acid NOME observed olivine oxyd particles Patrin pebbles polish porous porphyry present produced pudding-stone pumice pyrites quantity quartz remarkable resembling rock salt sand Saussure schistus schorl scoriæ seems Sicily side siderite silex siliceous singular slate smoke sometimes spar species specimens spots steatite stone strata substance sulphur surface tains thick tion tufo vapours veins Vesuvius vitreous volcanoes wacken Werner yellow
Popular passages
Page 363 - From many places of this space issue volumes of sulphureous smoke, which being much heavier than the circumambient air, instead of rising in it, as smoke generally does, immediately on its getting out of the crater, rolls down the side of the mountain like a torrent till coming to that part of the atmosphere of the same specific gravity with itself, it shoots off* horizontally, and forms a large track in the air, according to the direction of the wind, which, happily for us, carried it exactly to...
Page 340 - I viewed with astonishment the configuration of the borders, the internal sides, the form of its immense cavern, its bottom, an aperture which appeared in it, the melted matter which boiled within, and the smoke which ascended from it. The whole of this stupendous scene was distinctly displayed before me; and I shall now proceed to give some description of it, though it will only be possible to present the reader with a very feeble image, as the sight alone can enable him to form ideas at all adequate...
Page 521 - ... even to the sea." On the following day he ascended an eminence above the crater, from which he obtained a still more interesting view. " The crater," he says, " is very small ; I do not think it exceeds fifty paces in diameter, having the form of a funnel terminating in a point. During all the time I observed it, the eruptions succeeded with the same regularity as during the preceding night. The approach of the eruption is not announced by any noise or dull murmur in the interior of the mountain,...
Page 148 - ... uncovered immediately takes fire almost before the coal touches the earth ; the flame makes the soil hot, but does not consume it, nor affect what is near it with any degree of heat. If a cane, or a tube of paper, be set about two inches in the ground, confined and...
Page 337 - ConeofEum. to pass that tract which may properly be called the cone of Etna, and which, in a right line, is about a mile or somewhat more in length. This was extremely steep, and not less rugged, from the accumulated...
Page 538 - The subterraneous bellowings were heard without intermission, and sometimes in less than a quarter of an hour there were six or seven eruptions from the large furnace. The noise of the repeated claps, the quantity of huge stones that flew about on every side, the houses tottering to their very foundations, and the fire, which now appeared in open day, surpassed all that had hitherto happened, and formed a scene astonishing beyond description.
Page 336 - In several places, it is true, the scorize broke under my feet; and in others I slipped, and had nearly fallen into cavities from which I should have been with difficulty extricated. One of the three places pointed out by the guides had likewise, from its extreme heat, proved highly disagreeable ; yet...
Page 363 - On the contrary, the smoke when seen by Count Borch, at the intervals when the air was calm, arose perpendicularly to a great height, and afterwards fell, like white fleeces, on the top of the mountain. I shall not presume to doubt these two facts, though I observed neither of them. The two columns of smoke which I saw, though bent somewhat from the perpendicular by the wind, ascended with the usual promptitude of ordinary smoke (a certain proof that it was considerably lighter than the ambient air),...
Page 258 - By one of the palaces, that was at a little distance from the town, which was not overwhelmed with it, one may judge of the rest. It was an out-house of the family of the Francken, and...
Page 539 - Being got into this vapour, they felt a close suffocating heat, and found the water very hot ; upon which they directed their course toward a part of the island at the farthest distance from the large furnace. The fires, which still continued to burn, and the boiling of the sea, obliged them to take a great compass, and yet they felt the air about them very hot and sultry. Having encompassed the island, and surveyed it carefully from an adjacent one, they judged it to be two hundred feet above the...