formed.
Sulphur reflects electricity and--in the crystalline form--passes light.
This light-non-metal did the same sort of thing; it reflected light and
passed electricity. It was a conductor.

"Now we have the things we need, the matter to disintegrate, and the
matter to hold the disintegrating material in. We have two different
types of matter. The rest is obvious--but decidedly not easy. They have
done it, though; and after the war is over, there should be many of
their machines drifting about in space waiting to give up their
secrets."

Arcot Senior clapped his son on the back. "A fair foundation on which to
start, anyway. But I think it's time now that you got working on your
problem; and since I'm officially retired, I'm going downstairs. You
know I'm working in my lab on a method to increase the range and power
of your projector for the molecular motion field. Young Norris is
helping me, and he really has ideas. I'll show you our math later."

The party broke up, the three younger men staying in their own labs, the
older men leaving.

IV

The three immediately set to work. At Arcot's suggestion, Wade and Morey
attacked the plate of crystal in an attempt to tear off a small piece,
on which they might work. Arcot himself went into the televisophone room
and put through a second call to the Tychos Observatory, the great
observatory that had so recently been established on the frigid surface
of the Moon. The huge mirror, twenty feet in diameter, allowed an
immense magnification, and stellar observations were greatly
facilitated, for no one bothered them, and the "seeing" was always
perfect.

However, the great distance was rather a handicap to the ordinary
televisophone stations, and all calls put through to the astronomers had
to be made through the powerful sending station in St. Louis, where all
interplanetary messages were sent and received, while that side of the
Earth was facing the station; and from Constantinople, when that city
faced the satellite. These stations could bridge the distance readily
and clearly.

For several minutes Arcot waited while connections were being made with
the Moon; then for many more minutes he talked earnestly with the
observer in this distant station, and at last satisfied, he hung up.

He had outlined his ideas concerning the black star, based upon the
perturbation of the planets; then he had asked them to investigate the
possibilities, and see if they could f