careful touch on the Wave Generator is necessary as we are dealing with the powers of the whole world here.⁠ ⁠…”

A concerted ahhhh swept through the crowd as the Space Wave Tapper shivered a bit, then rose slowly into the air. The demonstrator stepped back and the toy rose higher and higher, bobbing gently on the invisible waves of magnetic force that supported it. Ever so slowly the power was reduced and it settled back to the table.

“Only $17.95,” the young man said, putting a large price sign on the table. “For the complete set of the Atomic Wonder, the Space Tapper control box, battery and instruction book⁠ ⁠…”

At the appearance of the price card the crowd broke up noisily and the children rushed away towards the operating model trains. The demonstrator’s words were lost in their noisy passage, and after a moment he sank into a gloomy silence. He put the control box down, yawned and sat on the edge of the table. Colonel Hawton was the only one left after the crowd had moved on.

“Could you tell me how this thing works?” the colonel asked, coming forward. The demonstrator brightened up and picked up one of the toys.

“Well, if you will look here, sir.⁠ ⁠…” He opened the hinged top. “You will see the Space Wave coils at each end of the ship.” With a pencil he pointed out the odd shaped plastic forms about an inch in diameter that had been wound⁠—apparently at random⁠—with a few turns of copper wire. Except for these coils the interior of the model was empty. The coils were wired together and other wires ran out through the hole in the bottom of the control box. Biff Hawton turned a very quizzical eye on the gadget and upon the demonstrator who completely ignored this sign of disbelief.

“Inside the control box is the battery,” the young man said, snapping it open and pointing to an ordinary flashlight battery. “The current goes