Vibrating one's vocal folds (singing or vocalising) is known by anthropologists as the first instrument, followed by clapping hands & slapping of thighs & other body parts, and then manipulating sticks & stones, and later drums with skins & flutelike man made instruments. All are instruments of music which one may use to convey a musical thought to another. The Mills Brothers were quite well known for using their instruments (voices) to convey the musical thoughts they conceived (the sounds of trombones, trumpets, and other instruments) to their aduiences. Ella Fitzgerald used her voice to perform a style of singing known as "scat" singing, and her voice was considered one of the instruments of the jazz ensemble in which she performed.