Carla Angrick, age 11, of Eugene, Oregon, for her question:

Is mercury mined as a liquid?

Cinnabar is a handsome, rusty red rock and mercury is a bright silvery metal. The two substances appear so different that any kinship seems impossible. Nevertheless, they are related chemicals. As a rule, you need to find a deposit of crusty cinnabar in order to extract a supply of shiny mercury.

Mercury is about as rare as silver and the deposits are few and far between. The slithery, silvery stuff is one of the basic chemical elements    the only metallic element that is a liquid at ordinary temperatures. Small amounts of it are found here and there but as a rule they are too rare to make mining worth while. These driblets of liquid mercury are often found around hot mineral springs, where seething ground water deposits them in crevices near the surface.

The major portion of the earth's mercury combines with sulphur to form mercuric sulfide. This chemical compound is crusty, rusty red or scarlet cinnabar. The valuable ore is worth mining when its mercury content is only 1/2 of one per cent. As a rule, the deposits are near the surface and most cinnabar mines go no deeper than 500 feet. The handsome red rock is hacked and shoveled from the mine and sent to a A special processing plant.

A prospector may test cinnabar by throwing a few of its bright red crumbs onto a hot bed of charcoal. If the sample is indeed cinnabar, the rocky material will vaporize and disappear. Amore revealing test may be made in a laboratory by heating a sample of cinnabar in a flask. The heat will separate the sulphur from the compound and change it to fumes that rise up and escape. A black ring forms in the flask and above it fine droplets of silvery mercury gather on the inside walls. If a needle is scraped through the mercury film, the tiny droplets congeal into larger heat fragments show how mercury can be extracted from cinnabar on a larger scale. The ore heated in big flasks until the sulphur separates from the valuable vapor price sulphur also is a valuable element, the flasks are fitted with tubes to capture and condense the escaping vapor. When the sulphur has vaporized, the silvery mercury is left behind. Mercury does not vaporize until it reaches a temperature of 675 degrees Fahrenheit. It does not freeze solid until  the temperature drops to 38 degrees below zero. Between this wide temperature range, mercury is a liquid metal. However, as it grows warmer, it expands at a perfectly even rate. This is why the silvery liquid is so useful in thermometers and other instruments designed to register changing temperatures. It expands and contracts the same exact amount as it gains or loses each degree of heat.

Mercury has been an object of wonder and admiration for ages. It was named for Mercury, the wing footed messenger god of the ancient world. The Greeks called it "hydragyrum," watery silver, and its name quicksilver means "live silver." The wonderful stuff has been extracted from a cinnabar mine in Spain since 800 B.C. The United States has valuable cinnabar mines in several western and soutfieru states, though we do not produce all the mercury we need. Extra supplies are imported, mostly from Spain and Italy.