Sandra Scheres, aged 12, of Washington, Ill. for her question:

What is the Bessemer process?

Coke, limestone and iron ore ‑ these bulky things must be brought together to make iron and steel. The iron is made first, The steel is made from the iron. It takes about two tons of iron ore, one ton of coke and half a ton of crushed limestone to make one ton of iron. Blast furnaces must melt this mixture to at least 3,000 degrees Fahrenheit, A sizable blast furnace can turn out 1500 tons of iron in 24 hours, And once started, a blast furnace is never stopped day or night except for repairs.

The smelted iron trickles out at the bottom of the furnace. It is called pig iron. In olden times, the molten iron ran out into molds that looked like a row of piglets. Some of this pig iron goes on its way‑to become steel. The world makes over 200 million tone of steel a year. Half of this mountain of metal is made in the United States.

There are several processes for turning iron into steel. About six tons in every hundred tons of American made steel is made by the Bessemer process. A row of these massive converters stands in a big steel mill. From time to time, thick brown smoke, streaked with sparks, pours from their open mouths. This is followed by fiery flames spitting thirty feet or more up into the air. Some of the mighty pear‑shaped monsters can purify 45 tons of iron into steel in fifteen minutes,,

Two inventors hit upon the same idea for making steel from molten iron. One was William Kelly, an iron maker of Kentucky. The other was Henry Bessemer, an Englishman. Both men noticed that molten iron grew hotter under a blast of cool air. Both realized that the molten metal was using oxygen in the draft to burn up impurities.

However, such a blow of air burns out more than impurities. It reduces the carbon and manganese necessary for sturdy steel. Bessemer's work was completed by Robert iw$het, who added a metal called spiegeleisen to the over‑purified steel, Spiegeleisen 1s made separately in a blast furnace from iron, manganese and carbon. Its addition to the blown steel made the Bessemer converter practical.

The Bessemer converter is hung between axles. It can be tipped to receive a load of molten iron or pour forth finished steel. When loaded, the wide mouth of the monster is pointed skyward. A pipe leads the blast of air up through the bottom of the pot. It rushes through at about 20,000 cubic feet a minute ‑ which is quite a blast,

The steel from this process is, of course, Bessemer steel. It is fine for pipes, wires and strong cables. It also does duty as sheet metal and certain machine parts.