I embraced the first opportunity that presented itself to read the works that Prof. Vaughn suggested, and sought him more than once to question further. However, he would not commit himself in regard to the possible existence of other forces than those with which we are acquainted, and when I interrogated him as to possibilities in the study of obscure force expressions, he declined to express an opinion concerning the subject. Indeed, I fancied that he believed it probable, or at least not impossible, that a closer acquaintance with conditions of matter and energy might be the heirloom of future scientific students. At last I gave up the subject, convinced that all the information I was able to obtain from other persons whom I questioned, and whose answers were prompt and positive, was evolved largely from ignorance and self-conceit, and such information was insufficient to satisfy my understanding, or to command my attention. After hearing Vaughn, all other voices sounded empty. I therefore applied myself to my daily tasks, and awaited the promised return of the interesting, though inscrutable being whose subterranean sojourneying was possibly fraught with so much potential value to science and to man. THE UNBIDDEN GUEST RETURNS TO READ HIS MANUSCRIPT. CONTINUING HIS NARRATIVE. CHAPTER XXV. THE MOTHER OF A VOLCANO.--"YOU CAN NOT DISPROVE, AND YOU DARE NOT ADMIT." A year from the evening of the departure of the old man, found me in my room, expecting his presence; and I was not surprised when he opened the door, and seated himself in his accustomed chair. "Are you ready to challenge my statements?" he said, taking up the subject as though our conversation had not been interrupted. "No." "Do you accept my history?" "No." "You can not disprove, and you dare not admit. Is not that your predicament?" he asked. "You have failed in every endeavor to discredit the truth, and your would-be scientists, much as they would like to do so, can not serve you. Now we will continue the narrative, and I shall await your next attempt to cast a shadow over the facts." Then with his usual pleasant smile, he read from his manuscript a continuation of the intra-earth journey as follows: "Be seated," said my eyeless guide, "and I will explain some facts that may prove of interest in connection with the nature of the superficial crust of the earth. This crystal liquid spreading before us is a placid sheet of water, and is the feeder of the volcano, Mount Epomeo." "Can that be a surface of water?" I interrogated. "I find it hard to realize that water can be so immovable. I supposed the substance before us to be a rigid material, like glass, perhaps." "There is no wind to ruffle this aqueous surface,--why should it not be quiescent? This is the only perfectly smooth sheet of water that you have ever seen. It is in absolute rest, and thus appears a rigid level plane."