OCR Text |
Show 204 TEAVELS AND ADVENTUEES LN THE FAE WEST. was'once a lake. The surface was covered with an efflorescence to the depth of a foot, more solid, however, as you dig into it, composed of impure alum, and most probably formed by the action of sulphuric acid on feldspathic rock. Further towards the base of the mountain which bounded it on the east side, I found large quantities of pure crystalized alum, and also pure sulphur. This efflorescence which covers the lake, might be composed by the spontaneous evaporation of a mixture of sulphate of iron, and tersulphate of alumina, excess of sulphuric acid being present. We with great caution commenced to walk over this surface, and discovered that it undulated with the weight of our bodies. I felt as if walking on thin ice, which bent, without breaking beneath my weight. As we approached the centre, we heard a roaring, which our Indian said was caused from "big fire below." I put my ear close to the earth, and was almost sure it proceeded from the escape of either gas or the passage of water. With a pickaxe, brought for exploring purposes, an orifice about a foot in diameter was dug. The axe was suddenly driven through, when a yellow, muddy liquid gushed forth in a continued stream. I tasted the liquid, when to my surprise, it was a strong acid, which immediately set my teeth on edge. Sulphuric acid in large proportions was present; this crust of over a mile in diameter, was resting on the surface of this immense body of diluted sulphuric acid. Oxide of iron in large quantities is to be found cropping out of the base of the mountains; sulphur in large quantities is also present. These materials, acted upon by volcanic heat, will produce a white powder, which partakes of the character of the substance, forming the covering to the lake. In the neighborhood of some volcanoes, sulphuric |