Though thin ice may be found in the quiet bays and inlets nearly every morning during the year, the expanse of the lake is never frozen even in the severest weather. A peculiarity about the lake is that not only will iron not rust when left in its waters, but that which was before rusted soon loses its scales of rust after being immersed a few days. Several steamers ply on the lake carrying chiefly ore and wool. Some of the islands in the lake are inhabited by Indians who eke out a precarious living. A civilization antedating that of the Incas formerly occupied the region about the lake, as is proved by the remarkable ruins along the shores concerning which the natives told the early Spaniards that they had no record. Three square miles are covered by these ruins, whose walls were made of immense blocks of stone most accurately fitted together, thus giving evidence of the great skill in stone-cutting possessed by the pre-Inca people. The Inca rulers had beautiful palaces and other edifices on some of the islands. Titicaca Island was regarded as sacred, and at the time of the Spanish conquest was the site of a large temple richly ornamented with gold and silver. Prospecting in the Andes is attended with great hardships. Few wild animals can be found to furnish food. Food and utensils must be carried on the backs of men, and the greatest difficulty is experienced in traversing the almost inaccessible steeps and deep ravines. Coal of inferior quality has been found near the shores of Lake Titicaca and is used by the steamers sailing on its waters. Many rich mineral lodes yet remain undiscovered, and a vast number of valuable mines languish for lack of capital to develop them. Frequent revolutions and the insecurity of private property prevent the investment of foreign capital. The Andes will continue to be a great storehouse of minerals for many years to come. [Illustration: Silver-smelting works at Cassapalca, on the Oroya Railroad, Peru, 13,600 feet high] Muffling the feet of the Peruvian Andes is a long narrow strip--drifting dunes of rock waste--known as the Atacama Desert. In comparison with this awful desert, the Sahara is said to be a botanical garden. Here during a part of the year a fierce, relentless sun pours down its burning rays on the shifting sands, keeping the air at a scorching heat both day and night. Formerly the region belonged to Bolivia, but it was annexed to Chile as a result of the war of 1881. For miles and miles not a blade of grass, not a tree, not a shrub is to be seen. All around is a bleak, barren waste destitute of water. Yet underneath these sands lie concealed immense deposits of "nitrates" of untold wealth.