one cause and that one is a patent impossibility. I haven’t a bit of equipment here, but I expect that I can get most of the stuff I want from the University of California across the bay at Berkeley. I can get a plane at Crissy Field. I’ll tell you what to do, Carnes. Get your burro train together and start as soon as you can, but leave me half a dozen burros and a guide at Fallon. I’ll get up there as soon as I can and I’ll try to overtake you before you get to the wreck. If I don’t, don’t disturb anything any more than you can help until my arrival. Do you understand?”
“I thought that you were on your vacation, Doctor.”
“Oh shut up! Like most of my vacations, this one will have to be postponed. I’ll move as swiftly as I can and I ought to be at Fallon to-night if I’m lucky and don’t run into any obstacles. Burros are fairly slow, but I’ll make the best time possible.”
“I rather expected you would, Doctor. I can’t get my pack train together until evening, so I’ll wait for you right here. I’m mighty glad that you are going to get in on it.”
Silently Carnes and Dr. Bird surveyed the wreck of the T. A. C. plane. The observations of the secret service operative had been correct. The bodies of the unfortunate crew had been broken into fragments. Their limbs had not been twisted off as a freak of the fall but had been cleanly broken off, as though the bodies had suddenly become brittle and had shattered on their impact with the ground. Not only the bodies, but the ship itself had been broken up. Even the clothing of the men was in pieces or had long splits in the fabric whose edges were as clean as though they had been cut with a knife.
Dr. Bird picked up an arm which had belonged to the pilot and examined it. The brittleness, if it had ever existed, was gone and the arm was limp.
“No rigor mortis,” commented the Doctor. “How long ago was the wreck?”
“About seventy-two hours ago.”
“Hm-m! What about those packets that were on the plane?”
Carnes stepped forward and gingerly inspected first the body of the army courier and then that of the courier of the T. A. C.
“Both gone, Doctor,” he reported, straightening up.
Dr. Bird’s face fell into grim lines.
“There is more to this case than appears on the surface, Carnes,” he said. “This was no ordinary wreck. Bring up that third burro; I want to examine these fragments a little. Bill,” he went on to one of the two guides who had accompanied them from Fallon, “you and Walter scout around the ground and see what you can find out. I especially wish to know whether anyone has visited the scene of the wreck.”
The guides consulted a moment and started out. Carnes drove up the burro the Doctor had indicated and Dr. Bird unpacked it. He opened a mahogony case and took from it a high powered microscope. Setting the instrument up on a convenient rock, he subjected portions of the wreck, including several fragments of flesh, to a careful scrutiny. When he had completed his observations he fell into a brown study, from which he was aroused by Carnes.
“What did you find out about the cause of the wreck, Doctor?”
“I don’t know what to think. The immediate cause was that everything was frozen. The plane ran into a belt of cold which froze up the motor and which probably killed the crew instantly. It was undoubtedly the aftermath of that cold which you felt when you swooped down over the wreck.”
“It seems impossible that it could have suddenly got cold enough to freeze everything up like that.”
“It does, and yet I am confident that that is what happened. It was no ordinary cold, Carnes; it was cold of the type that infests interstellar space; cold beyond any conception you have of cold, cold near the range of the absolute zero of temperature, nearly four hundred and fifty degrees below zero on the Fahrenheit scale. At such temperatures, things which are ordinarily quite flexible and elastic, such as rubber, or flesh, become as brittle as glass and would break in the manner which these bodies have broken. An examination of the tissues of the flesh shows that it has been submitted to some temperature that is very low in the scale, probably below that of liquid air. Such a temperature would produce instant death and the other phenomena which we can observe.”
“What could cause such a low temperature, Doctor?”
“I don’t know yet, although I hope to find out before we are finished. Cold is a funny thing, Carnes. Ordinarily it is considered as simply the absence of heat; and yet I have always held it to be a definite negative quantity. All through nature we observe that every force has its opposite or negative force to oppose it. We have positive and negative electrical charges, positive and negative, or north and south, magnetic poles. We have gravity and its opposite apergy, and I believe cold is really negative heat.”
“I never heard of anything like that, Doctor. I always thought that things were cold because heat was taken from them–not because cold was added. It sounds preposterous.”
“Such is the common idea, and yet I cannot accept it, for it does not explain all the recorded phenomena. You are familiar with a searchlight, are you not?”
“In a general way, yes.”
“A searchlight is merely a source of light, and of course, of heat, which is placed at the focus of a parabolic reflector so that all of the rays emanating from the source travel in parallel lines. A searchlight, of course, gives off heat. If we place a lens of the same size as the searchlight aperture in the path of the beam and concentrate all the light, and heat, at one spot, the focal point of the lens, the temperature at that point is the same as the temperature of the source of the light, less what has been lost by radiation. You understand that, do you not?”
“Certainly.”
“Suppose that we place at the center of the aperture of the searchlight a small opaque disc which is permeable neither to heat nor light, in such a manner as to interrupt the central portion of the beam. As a result, the beam will go out in the form of a hollow rod, or pipe, of heat and light with a dark, cold core. This core will have the temperature of the surrounding air plus the small amount which has radiated into it from the surrounding pipe. If we now pass this beam of light through a lens in order to concentrate the beam, both the pipe of heat and the cold core will focus. If we place a temperature measuring device near the focus of the dark core, we will find that the temperature is lower than the surrounding air. This means that we have focused or concentrated cold.”
“That sounds impossible. But I can offer no other criticism.”
“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,”
