Morgan Friedlander, age 10, of Haggerstown, Md., for his question:

WHAT IS KEROSENE?

Kerosene is an important petroleum product that is used chiefly as fuel. It is a product of petroleum refinery processes.

Kerosene is a mixture of hydrocarbons, which are compounds containing the elements hydrogen and carbon. This mixture boils between 150 and 300 degrees Celsius.

At one time, kerosene lamps were the chief source of artificial lighting. Kerosene lamps are still used in camping and for other purposes.

In the petroleum industry, kerosene is spelled "kerosine."

Abraham Gesner, a Canadian doctor and geologist, patented a distilling process for refining oil in 1854. He produced an improved lighting oil which he called kerosene. He derived the name from the Greek word "keros," which means "wax."

Gesner refined the oil from coal, and for this reason kerosene was and is still often called "coal oil."

Kerosene's greatest use today is in jet aircraft engines. Both turboprop and the conventional ramjet engines use it as a fuel. Commercial jet aircraft in the United States and Canada use kerosene. Military aircraft use a mixture of kerosene and gasoline.

Kerosene still supplies lighting and cooking fuel in areas far from electricity. Many farmers use kerosene to run tractors and other farm machinery. Kerosene also operates the electric generators that charge storage batteries on farms and in small villages.

Kerosene, in addition to being used as a fuel, is also used as a solvent for weed killers and insecticides.

Industry processes kerosene to remove impurities such as sulfur compounds and some of the aromatic hydrocarbons. The kerosene is treated with a suitable solvent like liquid sulfur dioxide, which dissolves some of the impurities. Usually this process is repeated several times.

In the U.S. today, about 250 million barrels of kerosene are produced each year.

The specific gravity, or "density," of kerosene is about 0.0800.

When kerosene is used as a solvent for weed killers and insecticides, a high aromatic hydrocarbon content is desirable because it makes the substance a better solvent. But the aromatics in kerosene produce a poor flame for lighting purposes, and much smoke.

"Hydrocarbon" refers to the most important class of organic compounds. They contain only the elements hydrogen and carbon. Commercial petroleum products such as kerosene, gasoline, lubricating oils and paraffin are mixtures of hydrocarbons.

Some hydrocarbons are found in coal tar and coal gas. Many others are synthesized or made artificially from hydrocarbons found in nature.