"You are peevish and exhausted, or you would perceive that I have generally allowed you to make the issue, and more than once have endeavored to dissuade you from doing so. Besides, did I not several times in the past bring experimental proof to dispel your incredulity? Have I not been courteous?" "Yes," I petulantly admitted; "yes." Then I determined to imitate his artful methods, and throw him upon the defensive as often as he had done with me. I had finally become familiar with his process of arguing a question, for, instead of coming immediately to his subject, he invariably led by circuitous route to the matter under discussion. Before reaching the point he would manage to commit me to his own side of the subject, or place me in a defenseless position. So with covert aim I began: "I believe that friction is one method of producing heat." "Yes." "I have been told that the North American Indians make fires by rubbing together two pieces of dry wood." "True." "I have understood that the light of a shooting star results from the heat of friction, producing combustion of its particles." "Partly," he answered. "That when the meteoric fragment of space dust strikes the air, the friction resulting from its velocity heats it to redness, fuses its surface, or even burns its very substance into ashes." "Yes." "I have seen the spindle of a wheel charred by friction." "Yes." "I have drawn a wire rapidly through a handkerchief tightly grasped in my hands, and have warmed the wire considerably in doing so." "Yes." I felt that I had him committed to my side of the question, and I prepared to force him to disprove the possibility of one assertion that he had made concerning his journey. "You stated that you rode in a boat on the underground lake." "Yes." "With great rapidity?" "Yes." "Rapid motion produces friction, I believe?" "Yes." "And heat?" "Yes." "Why did not your boat become heated even to redness? You rode at the rate of nine hundred miles an hour," I cried exultingly. "For two reasons," he calmly replied; "two natural causes prevented such a catastrophe." And again he warned me, as he had done before, by saying: "While you should not seek for supernatural agencies to account for any phenomena in life, for all that is is natural, neither should you fail to study the differences that varying conditions produce in results already known. A miracle ceases to be a miracle when we understand the scientific cause underlying the wonder; occultism is natural, for if there be occult phenomena they must be governed by natural law; mystery is not mysterious if the veil of ignorance that envelops the investigator is lifted. What you have said is true concerning the heat that results from friction, but-- "First, the attraction of gravitation was inconsiderable where the boat, to which you refer, rested on the water.