even this steam was as a brick wall to his probing touch. Miller started gloomily to thread his way through the waiters in back of the counter again.

Moments later he stood in the street and there were tears swimming in his eyes.

"Helen!" His voice was a pleading whisper. "Helen, honey, where are you?"

There was no answer but the pitiful palpitation of utter silence. And then, there was movement at Dave Miller's right!

Something shot from between the parked cars and crashed against him; something brown and hairy and soft. It knocked him down. Before he could get his breath, a red, wet tongue was licking his face and hands, and he was looking up into the face of a police dog!

Frantic with joy at seeing another in this city of death, the dog would scarcely let Miller rise. It stood up to plant big paws on his shoulders and try to lick his face. Miller laughed out loud, a laugh with a throaty catch in it.

"Where'd you come from, boy?" he asked. "Won't they talk to you, either? What's your name, boy?"

There was a heavy, brass-studded collar about the animal's neck, and Dave Miller read on its little nameplate: "Major."

"Well, Major, at least we've got company now," was Miller's sigh of relief.

For a long time he was too busy with the dog to bother about the sobbing noises. Apparently the dog failed to hear them, for he gave no sign. Miller scratched him behind the ear.

"What shall we do now, Major? Walk? Maybe your nose can smell out another friend for us."

They had gone hardly two blocks when it came to him that there was a more useful way of spending their time. The library! Half convinced that the whole trouble stemmed from his suicide shot in the head—which was conspicuously absent now—he decided that a perusal of the surgery books in the public library might yield something he could use.

That way they bent their steps, and were soon mounting the broad cement stairs of the building. As they went beneath the brass turnstile, the librarian caught Miller's attention with a smiling glance. He smiled back.

"I'm trying to find something on brain surgery," he explained. "I—"

With a shock, then, he realized 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