"You think he may be on the Northern inner side
of Tycho?"

"He may be anywhere," said Miko shortly.

"If you think that," Snap persisted, "suppose we swing the _Planetara_
over the South Pole. Tycho, viewed from there--"

"And take another quarter-day of time?" Miko sneered. "Flash on your
zed-ray; help him hook it up, Haljan."

[B] An allusion to the use of the zed-ray light for making
spectro-photographs of what might be behind obscuring rock masses,
similar to the old-style X-ray.

* * * * *

I moved to the lens-box of the spectroheliograph. It seemed that Snap
was very strangely reluctant: Was it because he knew that the Grantline
camp lay concealed on the north inner wall of Tycho's giant ring? I
thought so. But Snap flashed a queer look at Anita. She did not see it,
but I did. And I could not understand it.

My accursed, witless incapacity! If only I had taken warning!

"Here," commanded Miko. "A score of 'graphs with the zed-ray. I tell you
I will comb this surface if we have to stay here until our ship comes
from Ferrok-Shahn to join us!"

The Martian brigands were coming. Miko's signals had been answered. In
ten days the other brigand ship, adequately manned and armed, would be
here.

Snap helped me connect the zed-ray. He did not dare even to whisper to
me, with Moa hovering always so close. And for all Miko's sardonic
smiling, we knew that he would tolerate nothing from us now. He was
fully armed, and so was Moa.

I recall that Snap several times tried to touch me significantly. Oh, if
only I had taken warning!

We finished our connecting. The dull gray point of zed-ray gleamed
through the prisms, to mingle with the moonlight entering the main lens.
I stood with the shutter trip.

"The same interval, Snap?"

"Yes."

Beside me, I was aware of a faint reflection of the zed-light--a gray
Cathedral shaft crossing the helio-room and falling upon the opposite
wall. An unreality there, as the zed-light faintly strove to penetrate
the metal room-side.

I said, "Shall I make the exposure?"

* * * * *

Snap nodded. But that 'graph was never made. An exclamation from Moa
made us all turn. The Gamma mirrors were quivering! Grantline had picked
our signals! With what undoubtedly was an intensified receiving
equipment which Snap had not thought Grantline able to use, he had
caught our faint zed-rays, which Snap was sending only