"Instruments of percussion were few, and not indigenous to the Romans: such as were used came from the East, and were chiefly used in the worship of Eastern deities at Rome. When the worship of Bacchus was prohibited, they passed away with that licentious rite. The most complicated instrument of the ancient world appeared in Rome during the first century of our era. It was an _organ_, not, as in the scriptural days, a mere syrinx, or Pan's pipes, but an undoubted organ, somewhat similar in effect to our modern instrument. "The instrument is said to have been invented by Ctesbius of Alexandria in Egypt, who lived about 250 B.C. It did not appear extensively in Rome, however, until nearly three hundred years later. This organ has given rise to much fruitless discussion. In the field of musical history especially, 'a little' knowledge has proved 'a dangerous thing;' for, where slight descriptions exist of instruments of music, latitude is left for every writer to form his own theory, to fight for it, and denunciate those who differ from it. "We have seen what a battle was fought over the three little manuscripts of Greek music; what a host of differing opinions were held about the scriptural word 'Selah:' and now, about this hydraulic organ, each writer mounts his hobby-horse, and careers over the field of conjecture. Vitruvius has given a full description of the instrument from personal inspection; but as his technical terms have lost all significance to modern readers, and have been translated in various ways, and as his work contained no diagrams or illustrations of the various parts, it is useless. "Some writers imagine the organ to have had seven or eight stops,--that is, so many different _kinds_ of tones,--which would place them nearly on a par with our own. Others think that they possessed seven or eight _keys_; that is, so many _tones_ only. It has been a point of dispute as to what function the water performed in working it. Vitruvius is rather hazy on this point, saying only that it is 'suspended' in the instrument. The water, when the organ was played, was in a state of agitation, as if boiling. "There are medals still in existence which were awarded to victors in organ contests, on which this instrument is represented with two boys blowing or pumping; but the representation is too small to clear up any doubtful points." But, without devoting further space to the music that was in vogue prior to the Christian era, I proceed to notice that our first reliable account of it, as a system, commences with the fourth century; at which time St. Ambrose, Bishop of Milan, arranged the sacred chants that bear his name, and which were to be sung in the cathedrals.