formed since this cavern was hollowed out by the disturbing forces of nature. How did they find their way hither, you will perhaps ask. They came by water, not in large masses, but particle by particle, dissolved in the minute drops of fluid which percolated through the rocks overhead. May not the minerals have been introduced into the rock-cavities by water also? May not each detached and isolated nest of minerals be a miniature stalactite cavern?
"If the mineral contents of veins have not been deposited from aqueous solutions, they may have been introduced by sublimation. Many of the metals can be converted into vapour by intense heat; and provided it be possible for mineral vapours to gain access to fissures in rocks, it is not impossible for some of them to be condensed and deposited on the sides of the lodes.
"Gold ranks first among the metals, though its rarity renders it of less importance to man than some of the less perfect ones. This kingly metal occurs in almost every quarter of the globe, and is obtained by the miner either in the metallic or native state, from alluvial sands and gravels, or from veins in combination with silver, and often mixed with sulphides of other metals. In its native state it occurs in small crystals, in threads, or granular fragments, and in curiously shaped nuggets.
"Silver is a still more widely disseminated product of nature, occurring in veins in granitic moun-
