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قراءة كتاب Journal of Researches into the Natural History and Geology of the Countries Visited During the Voyage Round the World of H.M.S. Beagle Under the Command of Captain Fitz Roy, R.N.

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‏اللغة: English
Journal of Researches into the Natural History and Geology of the Countries Visited During the Voyage Round the World of H.M.S. Beagle Under the Command of Captain Fitz Roy, R.N.

Journal of Researches into the Natural History and Geology of the Countries Visited During the Voyage Round the World of H.M.S. Beagle Under the Command of Captain Fitz Roy, R.N.

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دار النشر: Project Gutenberg
الصفحة رقم: 6

placed on the ground. I observed that one which I kept in the cabin was slightly phosphorescent in the dark.


ST. PAUL'S ROCKS.—In crossing the Atlantic we hove-to, during the morning of February 16th, 1832, close to the island of St. Paul's. This cluster of rocks is situated in 0° 58' north latitude, and 29° 15' west longitude. It is 540 miles distant from the coast of America, and 350 from the island of Fernando Noronha. The highest point is only fifty feet above the level of the sea, and the entire circumference is under three-quarters of a mile. This small point rises abruptly out of the depths of the ocean. Its mineralogical constitution is not simple; in some parts the rock is of a cherty, in others of a feldspathic nature, including thin veins of serpentine. It is a remarkable fact that all the many small islands, lying far from any continent, in the Pacific, Indian, and Atlantic Oceans, with the exception of the Seychelles and this little point of rock, are, I believe, composed either of coral or of erupted matter. The volcanic nature of these oceanic islands is evidently an extension of that law, and the effect of those same causes, whether chemical or mechanical, from which it results that a vast majority of the volcanoes now in action stand either near sea-coasts or as islands in the midst of the sea.

The rocks of St. Paul appear from a distance of a brilliantly white colour. This is partly owing to the dung of a vast multitude of seafowl, and partly to a coating of a hard glossy substance with a pearly lustre, which is intimately united to the surface of the rocks. This, when examined with a lens, is

 

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