passed through the space between four large magnet-windings and a circular focus-coil. The beam came to a sharp, brilliant point an inch above the surface of a polished metal table.

"That is the prime focus," explained Peter. "It is at rest, but now I start the sweep circuits."

He pressed one button and the point of focus became a horizontal line while the converging beam changed from a true cone to a wedge-shaped figure, circular in cross section at the magnet-assembly and knife-edged above the table.

"Next, the vertical," said Peter. The wedge-shaped beam and the knife edge changed to become a square of brightness above the table. The cone of radiation became a transition-surface from circle to square as it crossed the space between magnet and tabletop.

"Now the traverse." The square of brightness dimmed and spread out to form a cube.

"We scan the volume like a three dimensional television raster," explained Peter. "Line after line moves down along a plane, and at the bottom of each plane the raster starts again at the top of the next plane." He eyed a couple of oscilloscope tubes critically. "This equipment has never been in full operation before," he said. "But it seems to be operating properly. So I will now put the first object—this cube of iron—on the transmitting table and send it out across the laboratory to be reassembled."

Peter shut the whole thing off with a single snap and disappeared around the edge of the shield. They saw him come into the enclosure from behind; in the mirror above, they saw him place the block of iron on the plate and set it very carefully. He left the shielded enclosure and was back in the open room in another half minute.

"Now!" he said with a feeling of mounting excitement.

Peter pressed the button.

The blue bombardment hit the metal cube and there hazed out in all directions an aura of pale ionization. From the centrix of this aureole there fanned out a spreading cone of blue that faded to invisibility as the spread reached the surface of the large parabolic reflector.

"The matter transmitter seems to be working perfectly," said Peter with a careful reading of his meters.

Walter Higgins snorted. He waved his cigar toward the far end of the laboratory. "How is your matter receiver doing?"

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