“Nevertheless, it is experimentally true. It is one of the facts which lead me to consider cold as negative heat. However, this is true of cold, as it is of the other negative forces; they exist and manifest themselves only in the presence of the positive forces. No one has yet concentrated cold except in the presence of heat, as I have outlined. How this cold belt which the T. A. C. plane encountered came to be there is another question. The thing which we have to determine is whether it was caused by natural or artificial forces.”
“Both of the packets which the plane carried are gone, Doctor,” observed Carnes.
“Yes, and that seems to add weight to the possibility that the cause was artificial, but it is far from conclusive. The packets might not have been on the men when the plane fell, or someone may have passed later and taken them for safekeeping.”
The doctor’s remarks were interrupted by the guides.
“Someone has been here since the wreck, Doctor,” said Bill. “Walter and I found tracks where two men came up here and prowled around for some time and then left by the way they came. They went off toward the northwest, and we followed their trail for about forty rods and then lost it. We weren’t able to pick it up again.”
“Thanks, Bill,” replied the doctor. “Well, Carnes, that seems to add more weight to the theory that the spot of cold was made and didn’t just happen. If a prospecting party had just happened along they would either have left the wreck alone or would have made some attempt to inter the bodies. That cold belt must have been produced artificially by men who planned to rob this plane after bringing it down and who were near at hand to get their plunder. Is there any chance of following that trail?”
“I doubt it, Doc. Walter and I scouted around quite a little, but we couldn’t pick it up again.”
“Is there any power line passing within twenty miles of here?”
“None that Walter and I know of, Doc.”