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On the existence of phosphoric acid in rocks of igneous origin

1851; Royal Society; Volume: 5; Linguagem: Inglês

10.1098/rspl.1843.0017

2053-9134

George Fownes, George Fownes,

Clay minerals and soil interactions

The author has, by careful analysis, ascertained the presence of phosphoric acid in various rocks of igneous origin. Those which he examined were principally the following; namely, 1. The fine white porcelain clay of Dartmoor, resulting from the disintegration of the felspar of the granite of that district. 2. Dark grey vesicular lava from the Rhine, used at Cologne as a building-stone. 3. White trachyte from the Drachenfels, near Bonn. 4. Dark red, spongy, scoriaceous lava from Vesuvius. 5. Compact, dark green basalt, or toadstone from Cavedale, Derbyshire. 6. Dark blackish-green basalt from the neighbourhood of Dudley, termed Rowley-ragg . 7. Ancient porphyritic lava, containing numerous crystals of hornblende, from Vesuvius. 8. A specimen of tufa, or volcanic mud, also from Vesuvius. The author infers from his analysis that phosphoric acid is a very usual component part of volcanic rocks, and is a principal source of the remarkable fertility possessed by soils derived from their disintegration.