alized he had been talking to himself.

In the next instant, Dave Miller whirled. A voice from the bookcases
chuckled:

"If you find anything, I wish you'd let me know. I'm stumped myself!"

* * * * *

From a corner of the room came an elderly, half-bald man with tangled
gray brows and a rueful smile. A pencil was balanced over his ear, and a
note-book was clutched in his hand.

"You, too!" he said. "I had hoped I was the only one--"

Miller went forward hurriedly to grip his hand.

"I'm afraid I'm not so unselfish," he admitted. "I've been hoping for
two hours that I'd run into some other poor soul."

"Quite understandable," the stranger murmured sympathetically. "But in
my case it is different. You see--I am responsible for this whole tragic
business!"

"You!" Dave Miller gulped the word. "I--I thought--"

The man wagged his head, staring at his note pad, which was littered
with jumbled calculations. Miller had a chance to study him. He was
tall, heavily built, with wide, sturdy shoulders despite his sixty
years. Oddly, he wore a gray-green smock. His eyes, narrowed and intent,
looked gimlet-sharp beneath those toothbrush brows of his, as he stared
at the pad.

"There's the trouble, right there," he muttered. "I provided only three
stages of amplification, whereas four would have been barely enough. No
wonder the phase didn't carry through!"

"I guess I don't follow you," Miller faltered. "You mean--something you
did--"

"I should think it was something I did!" The baldish stranger scratched
his head with the tip of his pencil. "I'm John Erickson--you know, the
Wanamaker Institute."

Miller said: "Oh!" in an understanding voice. Erickson was head of
Wanamaker Institute, first laboratory of them all when it came to
exploding atoms and blazing trails into the wildernesses of science.

* * * * *

Erickson's piercing eyes were suddenly boring into the younger man.

"You've been sick, haven't you?" he demanded.

"Well--no--not really sick." The druggist colored. "I'll have to admit
to being drunk a few hours ago, though."

"Drunk--" Erickson stuck his tongue in his cheek, shook his head,
scowled. "No, that would hardly do it. There must have been something
else. The impulsor isn't _that_ powerful. I can understand about the
dog, poor fellow. He must have been run over, and I caught him just at
the instant of passing from life to death."