DISAPPEARANCE OF VOLCANIC ISLANDS.
Many of the Volcanic Islands thrown up above the sea-level soon disappear, because the lavas and conglomerates of which they are formed spread over flatter surfaces, through the weight of the incumbent fluid; and the constant levelling process goes on below the sea by the action of tides and currents. Such islands as have effectually resisted this action are found to possess a solid framework of lava, supporting or defending the loose fragmentary materials.
Among the most celebrated of these phenomena in our times may be mentioned the Isle of Sabrina, which rose off the coast of St. Michael’s in 1811, attained a circumference of one mile and a height of 300 feet, and disappeared in less than eight months; in the following year there were eighty fathoms of water in its place. In July 1831 appeared Graham’s Island off the coast of Sicily, which attained a mile in circumference and 150 or 160 feet in height; its formation much resembled that of Sabrina.
The line of ancient subterranean fire which we trace on the Mediterranean coasts has had a strange attestation in Graham’s Island, which is also described as a volcano suddenly bursting forth in the mid sea between Sicily and Africa; burning for several weeks, and throwing up an isle, or crater-cone of scoriæ and ashes, which had scarcely been named before it was again lost by subsidence beneath the sea, leaving only a shoal-bank to attest this strange submarine breach in the earth’s crust, which thus mingled fire and water in one common action.
Floating islands are not very rare: in 1827, one was seen twenty leagues to the east of the Azores; it was three leagues in width, and covered with volcanic products, sugar-canes, straw, and pieces of wood.
PERPETUAL FIRE.
Not far from the Deliktash, on the side of a mountain in Lycia, is the Perpetual Fire described some forty years since by Captain Beaufort. It was found by Lieutenant Spratt and Professor Forbes, thirty years later, as brilliant as ever, and somewhat increased; for besides the large flame in the corner of the ruins described by Beaufort, there were small jets issuing from crevices in the side of the crater-like cavity five or six feet deep. At the bottom was a shallow pool of sulphureous and turbid water, regarded by the Turks as a sovereign remedy for all skin complaints. The soot deposited from the flames was held to be efficacious for sore eyelids, and valued as a dye for the eyebrows. This phenomenon is described by Pliny as the flame of the Lycian Chimera.
ARTESIAN FIRE-SPRINGS IN CHINA.
According to the statement of the missionary Imbert, the Fire-Springs, “Ho-tsing” of the Chinese, which are sunk to obtain a carburetted-hydrogen gas for salt-boiling, far exceed our artesian springs in depth. These springs are very commonly more than 2000 feet deep; and a spring of continued flow was found to be 3197 feet deep. This natural gas has been used in the Chinese province Tse-tschuan for several thousand years; and “portable gas” (in bamboo-canes) has for ages been used in the city of Khiung-tscheu. More recently, in the village of Fredonia, in the United States, such gas has been used both for cooking and for illumination.