"No ketchum letter, no ketchum Doctor," said the Indian laconically as he pumped another sh.e.l.l into his gun.

I was balked, until I noticed a pair of telephone wires running from the house to the tree to which one end of the chain was fastened.

"Is that a telephone to the house?" I demanded.

The Indian grunted an a.s.sent.

"Dr. Livermore telephoned me to come and see him," I said. "Can't I call him up and see if he still wants to see me?"

The Indian debated the question with himself for a minute and then nodded a doubtful a.s.sent. I cranked the old coffee mill type of telephone which I found, and presently heard the voice of Dr. Livermore.

"This is Tom Faber, Doctor," I said. "The _Graphic_ sent me up to get a story from you, but there's an Indian here who started to murder me when I tried to get past your barricade."

"Good for him," chuckled the Doctor. "I heard the shot, but didn't know that he was shooting at you. Tell him to talk to me."

The Indian took the telephone at my bidding and listened for a minute.

"You go in," he agreed when he hung up the receiver.

He took down the chain and I drove on up to the house, to find the Doctor waiting for me on the veranda.

"h.e.l.lo, Tom," he greeted me heartily. "So you had trouble with my guard, did you?"

"I nearly got murdered," I said ruefully.

"I expect that Joe would have drilled you if you had tried to force your way in," he remarked cheerfully. "I forgot to tell him that you were coming to-day. I told him you would be here yesterday, but yesterday isn't to-day to that Indian. I wasn't sure you would get here at all, in point of fact, for I didn't know whether that old fool I talked to in your office would send you or some one else. If anyone else had been sent, he would have never got by Joe, I can tell you. Come in. Where's your bag?"

"I haven't one," I replied. "I went to Calvada yesterday to see you, and didn't know until I got there that you were up here."

The Doctor chuckled.

"I guess I forgot to tell where I was," he said. "That man I talked to got me so mad that I hung up on him before I told him. It doesn't matter, though. I can dig you up a new toothbrush, and I guess you can make out with that. Come in."

I followed him into the house, and he showed me a room fitted with a crude bunk, a washstand, a bowl and a pitcher.

"You won't have many luxuries here, Tom," he said, "but you won't need to stay here for more than a few days. My work is done: I am ready to start. In fact, I would have started yesterday instead of to-day, had you arrived. Now don't ask any questions; it's nearly lunch time."

"What's the story, Doctor?" I asked after lunch as I puffed one of his excellent cigars. "And why did you pick me to tell it to?"

"For several reasons," he replied, ignoring my first question. "In the first place, I like you and I think that you can keep your mouth shut until you are told to open it. In the second place, I have always found that you had the gift of vision or imagination and have the ability to believe. In the third place, you are the only man I know who had the literary ability to write up a good story and at the same time has the scientific background to grasp what it is all about. Understand that unless I have your promise not to write this story until I tell you that you can, not a word will I tell you."

I reflected for a moment. The _Graphic_ would expect the story when I got back, but on the other hand I knew that unless I gave the desired promise, the Doctor wouldn't talk.

"All right," I a.s.sented, "I'll promise."

"Good!" he replied. "In that case, I'll tell you all about it. No doubt you, like the rest of the world, think that I'm crazy?"

"Why, not at all," I stammered. In point of fact, I had often harbored such a suspicion.

"Oh, that's all right," he went on cheerfully. "I _am_ crazy, crazy as a loon, which, by the way, is a highly sensible bird with a well balanced mentality. There is no doubt that I am crazy, but my craziness is not of the usual type. Mine is the insanity of genius."

He looked at me sharply as he spoke, but long sessions at poker in the San Francisco Press Club had taught me how to control my facial muscles, and I never batted an eye. He seemed satisfied, and went on.

"From your college work you are familiar with the laws of magnetism," he said. "Perhaps, considering just what your college career really was, I might better say that you are supposed to be familiar with them."

I joined with him in his laughter.

"It won't require a very deep knowledge to follow the thread of my argument," he went on. "You know, of course, that the force of magnetic attraction is inversely proportional to the square of the distances separating the magnet and the attracted particles, and also that each magnetized particle had two poles, a positive and a negative pole, or a north pole and a south pole, as they are usually called?"

I nodded.

"Consider for a moment that the laws of magnetism, insofar as concerns the relation between distance and power of attraction, are exactly matched by the laws of gravitation."

"But there the similarity between the two forces ends," I interrupted.

"But there the similarity does _not_ end," he said sharply. "That is the crux of the discovery which I have made: that magnetism and gravity are one and the same, or, rather, that the two are separate, but similar manifestations of one force. The parallel between the two grows closer with each succeeding experiment. You know, for example, that each magnetized particle has two poles. Similarly each gravitized particle, to coin a new word, had two poles, one positive and one negative. Every particle on the earth is so oriented that the negative poles point toward the positive center of the earth. This is what causes the commonly known phenomena of gravity or weight."

"I can prove the fallacy of that in a moment," I retorted.

"There are none so blind as those who will not see," he quoted with an icy smile. "I can probably predict your puerile argument, but go ahead and present it."

"If two magnets are placed so that the north pole of one is in juxtaposition to the south pole of the other, they attract one another,"

I said. "If the position of the magnets be reversed so that the two similar poles are opposite, they will repel. If your theory were correct, a man standing on his head would fall off the earth."

"Exactly what I expected," he replied. "Now let me ask you a question.

Have you ever seen a small bar magnet placed within the field of attraction of a large electromagnet? Of course you have, and you have noticed that, when the north pole of the bar magnet was pointed toward the electromagnet, the bar was attracted. However, when the bar was reversed and the south pole pointed toward the electromagnet, the bar was still attracted. You doubtless remember that experiment."

"But in that case the magnetism of the electromagnet was so large that the polarity of the small magnet was reversed!" I cried.

"Exactly, and the field of gravity of the earth is so great compared to the gravity of a man that when he stands on his head, his polarity is instantly reversed."

I nodded. His explanation was too logical for me to pick a flaw in it.

"If that same bar magnet were held in the field of the electromagnet with its north pole pointed toward the magnet and then, by the action of some outside force of sufficient power, its polarity were reversed, the bar would be repelled. If the magnetism were neutralized and held exactly neutral, it would be neither repelled nor attracted, but would act only as the force of gravity impelled it. Is that clear?"

"Perfectly," I a.s.sented.

"That, then, paves the way for what I have to tell you. I have developed an electrical method of neutralizing the gravity of a body while it is within the field of the earth, and also, by a slight extension, a method of entirely reversing its polarity."