made--thousands of
horsepower to do the work of a city, free thousands of men--made so
small you can hold it in one hand."

The sensitive face was proudly alight, proud and a trifle arrogant. The
exaltation of his coming power was strong upon him.

"Yes," said Professor Eddinger, "in one hand." And he raised his right
arm that he might see where the end of a sleeve was empty.

"I am sorry," said the inventor abruptly; "I didn't mean ... but you
will excuse me now; there is so much to be done--" But the thin figure
of Professor Eddinger had crossed to the far table to examine the
apparatus there.

"Crude," he said beneath his breath, "crude--but efficient!"

* * * * *

In the silence a rat had appeared in the distant corner. The Professor
nodded as he saw it. The animal stopped as the man's eyes came upon it;
then sat squirrellike on one of the shelves as it ate a crumb of food.
Some morsel from a hurried lunch of Avery's, the Professor
reflected--poor Avery! Yes, there was much to be done.

He spoke as much to himself as to the man who was now beside him. "It
enters here," he said and peered downward toward the lead bulb. He
placed a finger on the side of the metal. "About here, I should
think.... Have you a drill? And a bit of quartz?"

The inventor's eyes were puzzled, but the assurance of his old
instructor claimed obedience. He produced a small drill and a fragment
like broken glass. And he started visibly as the one hand worked
awkwardly to make a small hole in the side of the lead. But he withdrew
his own restraining hand, and he watched in mystified silence while the
quartz was fitted to make a tiny window and the thin figure stooped to
sight as if aiming the opening toward a far corner where a brown rat sat
upright in earnest munching of a dry crust.

The Professor drew Avery with him as he retreated noiselessly from the
instrument. "Will you close the switch," he whispered.

The young man hesitated, bewildered, at this unexpected demonstration,
and the Professor himself reached with his one hand for the black lever.
Again the arc crashed into life, to hold for a brief instant until
Professor Eddinger opened the switch.

"Well," demanded Avery, "what's all the show? Do you think you are
teaching me anything--about my own instrument?" There was hurt pride and
jealous resentment in his voice.

"See," said Professor Eddinger quietly. And his one thin hand pointed to
a f