“We talked it over carefully,” he went on, “bringing to bear all our power of analysis and habit of calm, scientific thought. We considered minutely the time element in the phenomena. Although the deep chanting began at the very moment of moonrise, fully five minutes had passed between its full lifting and the strange sighing sound from the inner terrace. I went back in memory over the happenings of the night before. At least ten minutes had intervened between the first heralding sigh and the intensification of the moonlight in the courtyard. And this glow grew for at least ten minutes more before the first burst of the crystal notes. Indeed, more than half an hour must have elapsed, I calculated, between the moment the moon showed above the horizon and the first delicate onslaught of the tinklings.