Robert Schaffer, age: 10, Coplay, Penna., for his question:

What is brown coal?

Coal gets its glo8sy black color from carbon. The more carbon it contains, the blacker it is. The morn carbon it contains, the more heat it can give. However, when it gets to be pure carbon, it is no use as a fuel. Mother Nature makes coil from old, vegetation and the recipe takes many millions of years to complete. During this time;, the original green trees, fallen logs, old leaves and banks of moss go through several stages. In one of theca. stages it is brown coal, which is also called lignite.

Beds of coal are being started right now to be ready millions of years in the future. The material now being used is mostly moss. Certain mosses grow in marshes and shallows stagnant lakes. Generations of mossy carpets grow one upon another. This old moss mixed with mud is cut out and dried. It is called peat and used as fuel. A peat fire gives off a fragrant smell, but since it contains only a little free carbon it cannot give off much heat. However, if left in the ground for a few million years, peat becomes brown coal. Brown coal has a little more carbon and, so makes a warmer fire.

The black coal we dig today was started arcs ago. Most of it was made from strange forests that grew in the Carboniferous Period of earth's history, some 250 million yours ago. This was the principle coal‑making age.

The forests of those far‑off days were like none that exist today. There were no oaks, elms, beeches or flowering plants. Instead., there were tree‑sized horsetails, giant canes, all sorts of ferns, large and small. About the only plants we would recognize were mosses and there were plenty of them.

This was a swampy period. The weird forests stood ankle deep in muddy water. The water was stagnant and therefore contained little or no free oxygen. The: bacteria t'uat cause dec ay need oxygen. So when the logs and leaves fell into the marsh water they did not rot. The wet forest floors were choked with piles of water‑logged. vegetation.

Times changed and the marshes drained dry. The layers of old vegetation were buried under new layers of dust and mud.. This put pressure and sometimes heat upon the layers of old vegetation. They suffered chemical changes. Hydrogen, oxygen and other substances were drawn, dried or squeezed out. In time, everything was lost but the carbon.

In the first stages, the old coal forests became layers of pulpy peat, As moisture and. other substances were lost, the peat became brown coal. This young coal was about 67 percent carbon. As the recipe  turgid, the brown coal became soft, black bituminous coal which. is about 88 portent carbon.

In places whore the crust of the earth folded and. bent, still more substances were removed from the coal. The result was hard, black anthracite coal, about 98 percent of which is carbon. In a few million years, our rich anthracite coal fields will become graphite, which is pure carbon and no use as a fuel at all.