Sometimes sea water is placed in great vats and evaporated. This leaves the salt, which is then refined. You know that the sun's heat causes the waters of a shallow pond to evaporate during warm weather. Shallow basins are often scooped out along the coast, and the waters which fill them are then shut off from the larger body. In time the water evaporates, and the salt, which has formed in thin layers, is collected. I said that most lakes are fresh-water bodies. There are some, however, that are _very_ salty. Great Salt Lake is one of these. Streams flow into it, but none flows out. If you were to bathe in the waters of this lake, you would find that your body would not sink. I have seen great piles of glistening salt along the shore of Great Salt Lake which had been obtained by evaporation. A railroad runs beside the lake, and the salt is loaded upon the cars to be hauled away. When the people first settled in Utah, they used to drive to the lake in wagons to get a supply of salt. Although the ocean and a few lakes contain immense quantities of this useful article, we get most of our supply from other sources. In the western part of New York State, at some distance below the surface of the earth, there is a thick layer of salt. Wells are drilled down to this; water is pumped into them, and then pumped out again as brine. This brine is evaporated in large pans made of iron, two quarts of brine yielding about a pound of salt. In China salt has been obtained in this way for hundreds and even thousands of years. Though they had little machinery to work with in those days, yet by patient, steady effort, they drilled wells two thousand and even three thousand feet in depth. From twenty-five to forty years were required to drill some of these wells. Those who commenced them knew that they were not likely to enjoy the fruits of their labor and that others must get the benefit of what they did. What does this show about these people? What benefits are you receiving from what others have done? Salt is also mined as coal and iron are. This is called _rock salt_. It is obtained in Germany, Poland, Austria, India, the United States, and in many other countries. One of the most interesting salt fields of the world is in the southeastern part of California. It is on the Colorado Desert, near the Colorado River. This was once a part of the ocean floor and the rocks contain much salt. Water seeping through the earth dissolves the salt and brings it to the surface at this place. What happens to the water? [Illustration: FIG. 31.--Harvesting Salt, Salton, California. Is there any Water in this Field?] [Illustration: FIG. 32.--Loading Cars with Salt. Salton, California.] This salt field covers an area of about one thousand acres, to a depth of from one to eight inches. You can see by the picture that it looks more like a field of snow and ice than one of salt. The bright sunlight is reflected from its surface with such power that it hurts one's eyes.