agated through ether, but they can
detect one such frequency or band of frequencies which they call
'infra-rays' and which are probably the fifth-order rays, since they lie
in the first level below the ether. The detector proper is a type of
lamp, which gives a blue light at the ordinary intensity of such rays as
would come from space or from an ordinary power plant, but gives a red
light under strong excitation."

"Uh-huh, I get that O. K.," said Seaton. "Rovol's
great-great-great-grandfather had 'em--I know all about 'em," Seaton
encouraged Drasnik, who had paused, with a questioning glance. "I know
exactly how and why such a detector works. We gave 'em an alarm, all
right. Even though we were working on a tight beam from here to there,
our secondary projector there was radiating enough to affect every such
detector within a thousand miles."

* * * * *

Drasnik continued: "Another significant fact is that a great many
persons--I learned of some five hundred, and there were probably many
more--have disappeared without explanation and without leaving a trace;
and it seems that they disappeared very shortly after our communication
was delivered. One of these was Fenor, the Emperor. His family remain,
however, and his son is not only ruling in his stead, but is carrying
out his father's policies. The other disappearances are all alike and
are peculiar in certain respects. First, every man who vanished belonged
to the Party of Postponement--the minority party of the Fenachrone, who
believe that the time for the Conquest has not yet come. Second, every
one of them was a leader in thought in some field of usefulness, and
every such field is represented by at least one disappearance--even the
army, as General Fenimol, the Commander-in-Chief, and his whole family,
are among the absentees. Third, and most remarkable, each such
disappearance included an entire family, clear down to children and
grand-children, however young. Another fact is that the Fenachrone
Department of Navigation keeps a very close check upon all vessels,
particularly vessels capable of navigating outer space. Every vessel
built must be registered, and its location is always known from its
individual tracer ray. No Fenachrone vessel is missing."

"I also sifted a mass of gossip and conjecture, some of which may bear
upon the subject. One belief is that all the persons were put to death
by Fenor's secret service, and that t