B890 <=> B892 [BTG XLI The bokharian dervish, p. 891]

“’Unfortunately for the Europeans, neither the first inventor nor the perfecter of that siren knew that sound can be obtained not only from the action of genuine vibrations but also from the simple flow of air; and as this siren of theirs sounds only from the flow of air and not at all from natural vibrations, therefore the determination of the exact number of vibrations by the indications of that siren is out of the question. . .

“’And, that sound can be produced from two causes, namely, from natural world–vibrations themselves and simply from the flow of air, is a very satisfying and interesting fact, and I shall now demonstrate it to you practically.’

“Having said this, the venerable Hadji stood up and brought from another section of the cave a pot of flowers in bloom, placed it in the center of that section of the cave, and then seated himself at the former monochord of the famous Pythagoras.

“Turning to us he said:

“’I will now produce from these combined pipes only five different tones of sound, and you please look attentively at this pot of flowers and look at your watches and notice how long I continue to produce these sounds and also remember the numbers indicated by the hands of the vibrometers for these sounds.’

“Then with a pair of small bellows he began to blow air into the corresponding pipes, which then began a monotonous melody of five tones.

“This monotonous melody continued for ten minutes and not only did we remember the numbers indicated by the hands of the vibrometers but all these five tones of sound were even very well impressed on our organs of hearing.