Kimberly Ayers, age 9, of Great Falls, Mont., for her question:

WHO INVENTED THE HARP?

The oldest stringed instrument in the world is the harp. Archaeologists have found one that was made by the Sumerians more than 4,500 years ago.

The Bible says that the harp was invented by Jubal. And we also know that it was the musical accompaniment for the psalms of the ancient Jews, and that it was played by David.

A double harp, called David's harp, is played with the fingers and thumbs of both hands. It is a triangular shaped instrument with a sounding board and catgut strings.

The strings of the double harp are usually tuned to the principal key of the music. Pressure of the thumb or a turn of the tuning pins allows the player to make a change in the pitch of the note that each of the strings will produce.

Perhaps the most important development of the instrument was the pedal harp, which many historians say was invented by Celestin Hochbrucker in about 1720. This harp has seven pedals which can make each note of the scale in each octave a half note higher.

A double action pedal harp was invented in 1810 by Sebastian Erard, and it is this harp that is played most often today. This harp allows two changes in the length of strings and thus two tone changes.

Through the years there have been many kinds of harps. The early ones were small and had only one or two. octaves.

The harp was the favorite instrument of the.old Irish poets and it has become one of the emblems of Ireland, like the shamrock.

The most common harp today is the large instrument which rests on the floor and is held between the knees of the seated player. It is used often in symphony orchestras and also as a solo instrument in concerts.

The autoharp is a more modern development. This instrument is held in the lap.

Related in name to the harp is the harpsichord, a musical instrument that actually resembles a piano. It can be played as a solo instrument, in a chamber music ensemble or with an orchestra.

Lighter and smaller than a piano, the instrument first appeared in the 1300s, but no one knows who invented it. By the 1700s, some of the harpsichords had two keyboards which were called manuals. Johann Sebastian Bach and other composers of the day wrote harpsichord music.

Strings on a harpsichord are stretched over two strips of wood called the bridge and the nut. The bridge is glued to a thin sheet of wood called.the soundboard and the nut is glued to a block of wood that runs parallel to the keyboard and holds the tuning pins. Like a regular harp, the strings of a harpsichord are plucked. They are not struck like those of a piano.