75. And while much such conversation as this was proceeding, on a sudden a noise was heard from some one of the neighbouring places, as from an hydraulic organ, very pleasant and agreeable, so that we all turned round towards it, being charmed by the melody; and Ulpian looking towards the musical Alcides said, Do you hear, O you most musical of men, this beautiful harmony which has made us turn round, being enchanted by the music? And is it not the case, as it is said to be among you Alexandrians, that constant music of an unaccompanied flute causes pain rather than any musical pleasure to those who hear it? And Alcides said,--But this engine, the hydraulic organ, whether you choose to class it among stringed instruments or among wind instruments, is the invention of a fellow-countryman of ours, an Alexandrian, a barber by trade; and his name is Ctesibius. And Aristocles reports this, in his book on Choruses, saying--"The question is asked, whether the hydraulic organ is a stringed instrument or a wind instrument." Now Aristoxenus did not feel sure on this point; but it is said, that Plato showed a sort of notion of the invention, making a nightly clock like the hydraulic organ; being very like an enormous hour-glass. And, indeed, the hydraulic organ does seem to be a kind of hour-glass. It cannot, therefore, be considered a stringed instrument, and one to be played by touching. But perhaps it may be called a wind instrument, because the organ is inflated by the water; for the pipes are plunged down into the water, and when the water is agitated by a youth, as the axles penetrate through the whole organ, the pipes are inflated, and emit a gentle and agreeable sound. And this organ is like a round altar; and they say that it was invented by Ctesibius the barber, who dwelt at that time in the territory of Aspendor, in the reign of the second Ptolemy surnamed Euergetes; and they say that he was a very eminent man; they say also, that he learnt a good deal from his wife Thais. But Trypho, in the third book of his treatise on Names, (and it is a dissertation on Flutes and Organs,) says Ctesibius the mechanic wrote a book about the hydraulis; but I am not sure that he is not mistaken as to the name. At all events, Aristoxenus prefers stringed instruments which are played upon by the touch to wind instruments; saying that wind instruments are very easy; for that many people, without having been taught, can play on the flute and pipe, as for instance, shepherds.