invisible forms—a man who had passed into an invisible state, or who could become invisible when sought.
Nothing approaching to the physical explanation of an echo can be framed by the uncivilized man. What does he know about the reflection of sound-waves?—what, indeed, is known about the reflection of sound-waves by the mass of our own people? Were it not that the spread of knowledge has modified the mode of thought throughout all classes, producing everywhere a readiness to accept what we call natural interpretations, and to assume that there are natural interpretations to occurrences not comprehended, there would even now be an explanation of echoes as caused by unseen beings.
That to the primitive mind they thus present themselves is shown by facts. Southey, writing of the Abipones, says that "what became of the Lokal" (spirit of the dead) "they knew not, but they fear it, and believe that the echo was its voice." Concerning the Indians of Cumana (Central America), Herrera tells us that they "believed the soul to be immortal, that it did eat and drink in a plain where it resided, and that the echo was its answer to him that spoke or called." And, narrating his voyage down the Niger, Lander says that "from time to time, as we came to a turn in the creek, the captain of the canoe halloed to the fetich, and, where an echo was returned, half a glass of rum and a piece of yam and fish were thrown into the water. When asked why, he said, 'Did you not hear the fetich?'"
Here, as before, I must ask the reader to ignore these special interpretations, acceptance of which forestalls the argument. Attention is now drawn to this evidence simply as confirming the inference that, in the absence of physical explanation, an echo is conceived as the voice of some one who avoids being seen. So that once more we have duality implied—of an invisible as well as a visible state.
To a mind unfurnished with any ideas save those of its own gathering, surrounding Nature thus presents multitudinous cases of seemingly-arbitrary change—now slight and slow, now gradual and great, now sudden and extreme. In the sky and on the earth, things make their appearance and disappear; and there is nothing to show why they do so. Here on the surface and there deeply embedded in the ground are things that have been transmuted in substance—changed from flesh to stone, from wood to flint. Living bodies on all sides exemplify metamorphosis in ways marvelous enough to the instructed, and to the primitive man quite incomprehensible. And this protean character which so many things around him exhibit, and which familiarize him with the notion that there are two or more interchangeable states of existence, is again impressed on him by such phenomena as shadows, reflections, and echoes.
Did we not thoughtlessly accept as innate the conceptions slowly elaborated during civilization and acquired insensibly during our early days, we should at once see that these ideas which the primitive man
