How should I prove all this? My first step was to visit the beautiful Iris Island, otherwise known as Goat Island. Donning a suit of oilcloth and other disagreeable loose stuff, I followed the guide into the Cave of the Winds. Of course, the sensation at first was so novel and overpowering that the question of pitch was lost in one of personal safety. Remaining here a few minutes, I emerged to collect my dispersed thoughts. After regaining myself, I returned at once to the point of beginning, and went slowly in again (alone), testing my first question of pitch all the way; that is, during the approach, while under the fall, while emerging, and while standing some distance below the face of the fall, not only did I ascertain this (I may say in spite of myself, for I could hear but one pitch), but I heard and sang clearly the pitch of all the harmonic or accessory tones, only of course several octaves higher than their actual pitch. Seven times have I been under these singing waters (always alone except the first time), and the impression has invariably been the same, so far as determining the tone and its components. I may be allowed to withhold the result until I speak of my experience at the Horseshoe Fall, and the American Fall proper--it being scarcely necessary to say that the Cave of the Winds is under the smaller cascade, known as the Central Fall. My next step was to stand on Luna Island, above the Central Fall, and on the west side of the American Fall proper. I went to the extreme eastern side of the island, in order to lose as far as possible the sound of the Central Fall, and get the full force of the larger Fall. Here were the same great ground tone and the same harmonics, differing only somewhat in pitch. I then went over to the Horseshoe Fall and sat among the Rapids. There it was again, only slightly higher in pitch than on the American side. Not then knowing the fact, I ventured to assert that the Horseshoe Fall was less in height, by several feet, than the American Fall; the actual difference is variously given at from six to twelve feet. Next I went to the Three Sister Islands, and here was the same old story. The higher harmonics were mostly inaudible from the noise of the Rapids, but the same two low notes were ringing out clear and unmistakable. In fact, wherever I was I could not hear anything else! There was no roar at all, but the same grand diapason--the noblest and completest one on earth! I use the word completest advisedly, for nothing else on earth, not even the ocean, reaches anywhere near the actual depth of pitch, or makes audible to the human ear such a complete and perfect harmonic structure. [Illustration: Horseshoe Falls from Below.]