There are many examples of this propagation of sounds which remain unheard in the intermediate space. I remember that a similar phenomenon has been observed in many places; amongst others on the internal surface of the gallery of the dome of St. Paul's in London, and especially in the midst of the curious caverns among the quarries near Syracuse, the most wonderful of which is called Dionysius' Ear.
Recuerdo varios lugares donde ha sido observado este fenómeno, pudiendo citar, entre otros, la galería interior de la cúpula de la catedral de San Pablo, de Londres, y, sobre todo, en medio de esas maravillosas cavernas de Sicilia, de esas latomías situadas cerca de Siracusa, la más notable de las cuales es la denominada la Oreja de Dionisio