Although small quantities of the nitrates had been sent to Europe for chemical purposes—chiefly the manufacture of gunpowder—no considerable amount was exported until a fortuitous discovery was made by a Scotchman named George Smith. After wandering over the world for some time Smith settled down in a little village near Iquique, where he had a small garden containing fruit-trees and flowers. In one part of his garden he noticed that the plants grew best where the soil contained a white substance.
He then proceeded to gather a quantity of the material and to experiment with it. To his surprise he found that a mere handful of it greatly stimulated the growth of plants. He told a member of his family in Scotland who was engaged in fruit-growing about the wonderful effects of the material as a fertilizer. As a result several bags of nitrates were distributed among Scottish farmers and fruit-growers. So satisfactory did the fertilizer prove that an immediate call was made for more of it. Thus began a business which now yields the owners of the beds one hundred million dollars yearly.
It was soon found out that the nitrate in its raw state contained properties that were injurious to plants and that these should be first eliminated. Forthwith reduction works were established to extract the deleterious substances. These substances were mainly iodine and bromine, two chemical elements that are of greater value than the nitrates themselves. Within a few years railroads were built to transport the nitrates from the beds to the various ports where the reduction factories were erected.
Many men who had large interests in the nitrate beds became immensely wealthy in a short time. The great value of the deposits caused towns and cities to spring up along the coast in the most inhospitable places, to some of which water was piped a distance of more than two hundred miles and at the cost of many millions of dollars.
The principal nitrate beds are in a shallow valley, four or five thousand feet above sea level, lying between a long range of hills and the base of the Andes. Just how these mineral deposits were formed it is difficult to explain, the most plausible theory being that this desert was once the bottom of an inland sea having vast quantities of seaweed covered with sand. In the gradual decay of this substance the nitrate of soda, or "Chile saltpetre," was formed.
To obtain the nitrates it is necessary first to remove the top layer of sand and then a layer of clay. Underneath this is found a layer of soft, whitish material called "nitrate." The crude nitrate is sent to the nitrate ports to be crushed and boiled in sea-water. After boiling, the solution is drawn off into shallow vessels and exposed to the heat of the sun to evaporate.
When nearly all has been evaporated and the remaining liquid drawn off, the bottom and sides of the vessels are found to be covered with sparkling white crystals. This is the saltpetre of commerce, the highest grade of which is used in the manufacture of gunpowder, the second grade for chemical purposes, and the third grade, the great bulk, for fertilizing the exhausted soils of Europe.
The liquid drawn off is crystallized by chemical treatment and further evaporation, and from it is obtained iodine, an ounce of which is worth as much as one hundred pounds of saltpetre. From eighty to one hundred million dollars' worth of these nitrates are dug out and sold each year. Great Britain takes about one-third of the entire product and Germany one-fifth.
Iquique has the largest shipping trade. From this port about fifty million dollars' worth of nitrates and three million dollars' worth of iodine are exported yearly.