Ann Patterson, age 16, of Helena, Mont., for her question:

WHEN WAS THE ROSETTA STONE FOUND?

A stone of black basalt 11 inches thick, 3 feet, 9 inches high and 2 feet, 4 1/2 inches across is the key to the long forgotten language of ancient Egypt. Called the Rosetta Stone, it was found half buried in the mud near the Rosetta mouth of the Nile River in 1799 by a French officer of Napoleon's engineering corps.

The Rosetta Stone was later taken to England, where it is still preserved in the British Museum.

On the stone is carved a decree by Egyptian priests to commemorate the crowing of Ptolemy V Epiphanes, king of Egypt from 203 to 181 B.C. The first inscription is in ancient Egyptian hieroglyphics. The second is in Demotic, the popular language of Egypt at that time. At the bottom of the stone the same message is written again in Greek.

A French scholar named Jean Francois Champollion studied the stone and made the first translation of the Greek. He was then able to pick out the Egyptian text and learn the meaning of the Egyptian hieroglyphic characters.