ly unfamiliar apparatus ranged along the opposite wall,
giving the room the appearance of being a laboratory of some kind.

* * * * *

Gordon's obvious bewilderment seemed to amuse the bluish-gray
monstrosity. "May I introduce myself?" he asked with a mocking note in
his metallic voice. "I am Arlok of Xoran. I am an explorer of Space,
and more particularly an Opener of Gates. My home is upon Xoran, which
is one of the eleven major planets that circle about the giant
blue-white sun that your astronomers call Rigel. I am here to open the
Gate between your world and mine."

Gordon reached a reassuring hand over to Leah. All memory of their
quarrel was obliterated in the face of their present peril. He felt
her slender fingers twine firmly with his. The warm contact gave them
both new courage.

"We of Xoran need your planet and intend to take possession of it,"
Arlok continued, "but the vast distance which separates Rigel from
your solar system makes it impracticable to transport any considerable
number of our people here in space-cars for, though our space-cars
travel with practically the speed of light, it requires over five
hundred and forty years for them to cross that great void. So I was
sent as a lone pioneer to your Earth to do the work necessary here in
order to open the Gate that will enable Xoran to cross the barrier in
less than a minute of your time.

* * * * *

"That gate is the one through the fourth dimension, for Xoran and your
planet in a four-dimensional universe are almost touching each other
in spite of the great distance separating them in a three-dimensional
universe. We of Xoran, being three-dimensional creatures like you
Earthlings, can not even exist on a four-dimensional plane. But we
can, by the use of apparatus to open a Gate, pass through a thin
sector of the fourth dimension and emerge in a far distant part of our
three-dimensional universe.

"The situation of our two worlds," Arlok continued, "is somewhat like
that of two dots on opposite ends of a long strip of paper that is
curved almost into a circle. To two-dimensional beings capable only of
realizing and traveling along the two dimensions of the paper itself
those dots might be many feet apart, yet in the third dimension
straight across free space they might be separated by only the
thousandth part of an inch. In order to take that short cut across the
third dimension