bisected along mathematically straight lines as if by gigantic saws, crushed. Some have even been found with no marks whatsoever of violence evidenced. You mean to imply that the force causing these deaths is not material?"
Sellers glowered.
"I imply nothing of the kind. Aside from the psychic fear induced by the presence of the Enemy at the point of attack-—indeed, preceding the attack, we know that in some way they are very material. But how and in what way we do not know. It is a simple law of the ancient science that action begets reaction. The reaction in this case is death, a material fact. The action is unknown. Either we are the victims of some colossal purely psychological attack or else the laws of nature have altered."
Payton grunted.
What could remain unchanged in that hell above?"
Weyman impatiently thrust forward.
"Have you the necessary equipment to construct this apparatus?"
"We shall be forced to demolish some of the more delicate inter-level communications machinery. But inasmuch as most of this is not operating anyway, there is small loss. The main thing I have to worry about is the strain on my mechanics. There aren't many left and we are all weak. My original estimate of the time required for its construction is probably understated."
"Well," commented Payton, wearily, "let us lose no further time. You have the necessary equipment and men. Begin building at once."
They finished Seller's machine at the enormous expenditure of six hundred hours of work and the lives of four irreplaceable men who dropped from utter exhaustion at the gruelling labor. Slowly the atmosphere was becoming poisonously tainted. And the lighting system was beginning to break down beyond repair. The City was now illuminated by bulbs lit at emergency spots. Everything else but the control room was in murky darkness.
The first trial was conducted in the control room in the presence of the Chief and the section heads. Several mechanics rolled the heavy detector into position. For once the room was brilliantly illuminated. Under the rays of twenty tremendous lighting units, the group gathered about the intricate construction of tangled wiring and humming motors. Sellers got up in the operator's chair, masked his face with a pair of heavy goggles and turned on the power.
A rising whine began.
The Chief sat up in his chair and stared. His sleepy mind was awake at last. He gripped the arms of his chair tensely.
The whine grew shriller and more penetrating. Sellers reached out a hand and adjusted some small controls. Now a thin aura of electric blue gathered about the machine and its operator and deepened in hue. The motors spun and hummed and spat sparks. The smell of ozone made them cough.
"Sixty decillion per second," Sellers spoke slowly through the lower half of the mask, "nothing on the macro-waves." He depressed his seat and threw
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