Note 53 — SECTION II. PHYSICAL GEOGRAPHY OF ICELAND.
Reading edition
From Palagonia in Sicily, where it was first described (1838) by that savant (see pp. 222-483, and 802, Dana’s System of Mineralogy, Trübner, London, 1871). The specific gravity is 2·43, and the fracture mostly conchoidal. The distinguished chemist, Professor Bunsen (Sect. ix., § 1), who, succeeding in producing artificial Palagonite, gives it iron, either magnetic or peroxide, and “some alkali,” a vague term: Dr W. Lauder Lindsay adds minor constituents, felspar, augite (hornblende), jasper, olivine, obsidian, hornstone, chalcedony, and zeolite. Professor Tyndall (Royal Institution, June 3, 1853) offers the following table:
Oxide of iron,36·75
Alumina,25·50
Lime,20·25
Magnesia,11·39 (not found by Dr Murray Thomson).
Soda,3·44
Potash,2·67
100·00
In 1872, only a single and a very poor specimen of this highly interesting rock had found its way to the museum in Jermyn Street.