you have walked this distance without becoming wearied, and you could not, without great fatigue, have ascended for so long a period. You are entering a zone of inner earth light; we are in the surface, the upper edge of it. Let us hasten on, for when this cavern darkness is at an end—and I will say we have nearly passed that limit—your courage will return, and then we will rest."
"You surely do not speak the truth; science and philosophy, and I am somewhat versed in both, have never told me of such a light."
"Can philosophers more than speculate about that which they have not experienced if they have no data from which to calculate? Name the student in science who has reached this depth in earth, or has seen a man to tell him of these facts?"
"I can not."
"Then why should you have expected any of them to describe our surroundings? Misguided men will torture science by refuting facts with theories; but a fact is no less a fact when science opposes."
I recognized the force of his arguments, and cordially grasped his hand in indication of submission. We continued our journey, and rapidly traveled downward and onward. The light gradually increased in intensity, until at length the cavern near about us seemed to be as bright as diffused daylight could have made it. There was apparently no central point of radiation; the light was such as to pervade and exist in the surrounding space, somewhat as the vapor of phosphorus spreads a self-luminous haze throughout the bubble into which it is blown. The visual agent surrounding us had a permanent, self-existing luminosity, and was a pervading, bright, unreachable essence that, without an obvious origin, diffused itself equally in all directions. It reminded me of the form of light that in previous years I had seen described as epipolic dispersion, and as I refer to the matter I am of the opinion that man will yet find that the same cause produces both phenomena. I was informed now by the sense of sight, that we were in a cavern room of considerable size. The apartment presented somewhat the appearance of the usual underground caverns that I had seen pictured in books, and yet was different. Stalactites, stalagmites, saline incrustations,
