The Arab, journeying over the yellow sands, riding upon the back of his faithful "ship of the desert," often looks longingly for some sign of water to cool his parched lips. The sailor may ride upon the beautiful blue waters of the ocean in his white-winged ship; but although there is nothing but water to greet his eyes, he cannot drink it, for it is bitter to the taste.

If you were to place a quantity of ocean water over a fire and evaporate it, there would remain a white substance. This is common salt. You see that it is as necessary to provide fresh water when one wishes to cross the ocean, as it is if one is going to cross the desert.

Most streams and lakes contain fresh water, so you will wonder why the waters of the ocean are briny. The rocks and soil of the earth contain salt, and the streams wash it from the land. Each one carries so little that we do not notice it, but they have worked so steadily and so long, that they have carried a great amount to the sea. None of it can escape, so the ocean gets more and more briny.

No healthy person would ever think of eating salt alone as a food, and yet our food would taste very unsatisfactory without it. Farmers supply their cattle and horses with salt, and wild animals search for it in the forests, and lick it from the soil with their tongues.

Salt is so important to us that I want to tell you about some of the ways in which men obtain it.

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?

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.

A great plow drawn by a steam engine moves over this dazzling field, and throws the salt up in furrows. It is then piled up, loaded on to cars, and taken to sheds, where it is purified. Indians and Japanese do most of the work.

In order to purify the brines they are boiled in iron pans and treated in various ways to make them fit for table use. When evaporation is rapid, the salt crystals are quite small, but slower evaporation produces larger ones. Rock salt is dissolved in water and then evaporated. To get the finest of salt, the crystals must be ground. When salt is to be used for other purposes than to season food, not so much pains are taken. Name other uses of salt.

In olden times, when salt was not so easily obtained as it is to-day, it was regarded in some countries as a luxury. This seems strange, does it not? At one time the Chinese made it into little cakes, stamped the image of the emperor upon it, and used it as money. In Arabia those who together ate food which had been salted, believed that this established a special bond of friendship between them. This led to the old saying, "There is salt between us."