As my mind reeled amidst this chaos, I became conscious of a mixed grating and whirring from all three of the machines lately linked to the cylinder—a grating and whirring which soon subsided into a virtual noiselessness. What was about to happen? Was I to hear a voice? And if so, what proof would I have that it was not some cleverly concocted radio device talked into by a concealed but closely watched speaker? Even now I am unwilling to swear just what I heard, or just what phenomenon really took place before me. But something certainly seemed to take place.