Note 5 — Chapter VI · TRACHYTE AND BASALT.—DISTRIBUTION OF VOLCANIC ISLES.
Reading edition
Trachyte from Java was found by Von Buch to be 2·47; from Auvergne, by De la Beche, it was 2·42; from Ascension, by myself, it was 2·42. Jameson and other authors give to basalt a specific gravity of 3·0; but specimens from Auvergne were found, by De la Beche, to be only 2·78; and from the Giant’s Causeway, to be 2·91.