Billy Jarosio, Age 10, of San Diego, Calif., for his question:
Where do we get iodine?
You would never suspect that iodine was discovered because of Napoleon. You would never guess that the stinging brown liquid you paint on a scratch was named for a purple flower. And you would never think of half the places over land and sea where we go in search of iodine.
When Napoleon went to war, the best brains in France searched for ways to help him. Nicolas Appert invented a way to can meat to feed his soldiers far from home. Bernard Courtois searched in seaweed for an ingredient to make gunpowder. He found a by product., a mysterious crystal substance of violet blue. A French chemist then proved that these crystals contained a new element. He named it iodine from the Greek word for violet.
Iodine was discovered in 18.. It is one of the world's basic chemical elements and quite plentiful. Moreover, traces of iodine are needed by both plants and animals. You may wonder why this vital element was not discovered sooner, but there is reason why it was not. Iodine is very hard to find. However, it is findable when you know where to look for it.
Iodine is a very active element, akin to chlorine which is strong enough to kill germs and bleach fabrics. Because it is so active, iodine is always eager to combine with other elements. In nature, we never find it in its pure form. It unites with other elements to form compounds of iodine.
There are iodine salts in the air above the ocean and there is plenty of iodine in sea water. There is still more iodine in seaweeds and marine animals, in ground water and brine, and in the salty water often buried along with petroleum. We can extract iodine from all these sources. But the bulk of the world's supply comes from a rocky ore.
Iodine ore is called sodium nitrate or saltpeter and it abounds in the deserts of Chile. Tons of saltpeter are mined in Chile and processed to extract its iodine and various iodine compounds. In California and Louisiana, iodine is extracted from sodium iodite which is present in brine wells. Most of our iodine comes from these briny wells. The bulk of the world supply comes from the saltpeter mines of Chile.
The tincture of iodine used as a germicide is a solution of alcohol and dissolved iodine. Pure iodine is a dense solid. It is a crystalline substance which gleams with a blue black lustre. When heated, this element does not melt into a liquid. At about 184 degrees Centigrade, it turns directly into a purple vapor.