Page:Popular Science Monthly Volume 21.djvu/583

Rh places and rise of rocks of considerable magnitude. The salt-bearing rocks are of a reddish color, receiving their tint from red ochre, which, associated to a small extent with specular iron, covers the salt deposit and is more or less mixed with it imparting to it also a red tint. The association of ochre with salt is so constant in the district that the existence of the former is almost a sure indication of the presence of the latter. Hear the village of Kowim on the Island of Kishm, the salt and ochre are so mingled in a part of the range as to give it the appearance of a structure made of red bricks and mortar. Years ago, the salt was gathered from hollows in the ground where briny water issuing from the rocks could be collected and the mineral would be left after evaporation in beautiful crystalline masses. More recently, the salt has been quarried; and the works conducted for this purpose have become large caverns in

which stalactites have been formed from the trickling of the brine, yielding snow-white masses of saccharoid salt. Besides these masses, the salt is found here in pure white lumps, easily reduced to granules, the most valuable form, red, stony masses which are used chiefly for salting fish, and translucent and transparent masses of cubical forms, and is dug out with crow-bars. At Hameran, four miles from the sea-shore, the salt is found in beds about four feet thick with intervening layers of earthly material, and is sometimes of a pale-greenish color from contact with an earth containing manganese. The masses in these beds are broken with gunpowder and granulated with mallets. Warm springs charged with salt are found close by the village of Salakh, near Henjam, yielding a reddish naphtha which the natives use for purposes of light and for rheumatic complaints.

The Great Arctic Forest.—Professor Nordenskiold, in his "Voyage of the Vega," describes what he calls the greatest forest the earth has to show. It exists in the country of the Yenisei River, and extends from the fifty-eighth or fifty-ninth degree of latitude to far north of the Arctic Circle, in the neighborhood of the sixty-ninth degree of latitude, covering an extent of about one thousand kilometres from north to south, and perhaps four limes as much from east to west. "It is," he says, "a primeval forest of enormous extent, nearly untouched by the axe of the cultivator, but at many places devastated by forest-fires. On the high eastern bank of the Yenisei the forest begins immediately at the riverbank. It consists principally of pines. . . . Most of these already north of the Arctic Circle [the traveler is supposed to be going from north to south] reach a colossal size, but in such a case are often here, far from all forestry, gray and half-dried up with age." The ground is covered with fallen branches and stems in all stages of rottenness, which are covered, often concealed, by an exceedingly luxuriant bed of mosses, while tree lichens occur sparingly. "The pines, therefore, want the shaggy covering common in Sweden, and the bark of the birches which are seen here and there among the pines is distinguished by an uncommon blinding whiteness." Evidence was collected to show that the limit of trees in the Yenisei region has extended, even during our geological period, farther north than now.

Mud-Volcanoes in Sicily.—Two eruptions of mud in places remote from each other, and offering different and remarkable characteristics, are under observation in Sicily. One is taking place in the interior of the island, about eight miles north of Girgenti. It proceeds from a mountain about three hundred feet high, called Macaluba, the flattened summit of which is dotted with small cones, each containing a tunnel shaped crater, from the bottom of which a bubble of mud rises and bursts every minute. The other eruption is near Paterno, on the western side of the lower region of Etna, nearly forty miles west of Macaluba, and takes place in openings and small cones on the level of the surface. It is considerably more violent than that of Macaluba. The mud spurts out in jets several yards high, and forms a large fuming lake, which rims into the bed of the river Sinet. The eruption has been renewed three times within a year, and is at present accompanied with deep subterranean rumblings and strong tremors of the earth, some of which are perceptible several miles away. The mud that issues from these volcanoes is saline