Page:Popular Science Monthly Volume 26.djvu/501

Rh by the miners, and mainly composed of gypsum. This has resulted from the oxidation of the sulphur to sulphuric acid by atmospheric agency, the acid in turn attacking the lime carbonate, and forming sulphate (gypsum). The most plausible supposition as to the origin of the sulphur-seams would appear to be that the lakes received streams of water containing calcium sulphide in solution, this calcium sulphide probably resulting from a reduction of the masses of calcium sulphate (gypsum) by the action of volcanic heat. Gradual decomposition of the calcium sulphide in the presence of water would finally result in a deposition of sulphur and of lime carbonate, in the relative proportions of twenty-four and seventy-six per cent. As a matter of fact, much of the Sicilian ore actually has this percentage composition. Whatever the process has been, it is no longer in activity, and there is no growth nor renewal of the beds, in this respect differing essentially from recent deposits due to "living" solfataric action.

Almost all the Sicilian ore is carried to the surface on boys' backs, consequently it does not pay to work below about four hundred feet, as it then becomes necessary to employ hauling machinery. Hence the deposits lying below that horizon are hardly touched, and as many of the beds are nearly vertical, and do not diminish in yield as they descend, the still untouched resources must be very great. Various estimates have been made as to the period for which the supply will last at the present rate of consumption; these range from fifty to two hundred years. There are said to be about two hundred and fifty mines in the island, and no less than 4,367 calcaroni were reported in operation fifteen years ago. The average yield is stated not to exceed fourteen per cent.

In the province of Murcia, and at other places, in Spain, the existence of fine beds of sulphur has been ascertained. One is worked by an English association, the Hellin Sulphur Company. The quality is very good.

A sulphur-deposit exists at Djemsa, in a perfectly rainless desert on the African coast near Suez, very near the sea, and constituting a hill six hundred feet high, whose sides are blasted down as in quarrying stone. Some two hundred Arabs, employed under French engineers, succeeded in mining ten tons a day. A similar deposit occurs at Ranga, five hundred miles from Suez, also near the coast of the African Continent, which differs only in being buried under other strata, so that mining is necessary.

The Gunong Jollo, or sulphur mountain of the Sunda Islands, lies southwest of the village Prado, and southeast of Dompo. The sulphur is dug from three places in an old crater now in the solfataric stage of its existence. Each spot is one hundred to one hundred and twenty roods long, and fifty to sixty broad. The sulphur collects between masses of white stone (perhaps decomposed trachyte), and sometimes covers a space of one to three roods square. On the liquid and warm