The New International Encyclopædia/Principal (organ stop)

PRINCIPAL. The name given to an important stop of the organ, of 4-foot pitch on the manual, and 8-foot pitch on the pedal. It is sometimes termed the octave stop, because it is tuned one octave above the diapasons. It stands midway in pitch between the diapasons and the fifteenth; and in tuning an organ it is, owing to its clearness of tone, the best stop to begin with for the adjustment of other stops; probably from this fact it derives its name. See Organ.