t of light from a powerful electric bulb. The shorter of them
was saying to a third man, who knelt in front of the dynamo:

"On full." Then, as a full-throated drone pulsed from it: "Zenalishin
iss there? Yess. Put him in."

The voice of the hissing s's--that was Istafiev. Short, stocky,
black-haired, he was a direct contrast to the tall figure next him of
one whose pointed black beard gave elegance to sharp, thin features.
He carried a gun at his waist, and he identified himself as Kashtanov
by saying languidly:

"Better strap him in. He'll fall, otherwise. Get some cord; I'll lift
him."

The other man, by the dynamo, apparently a subordinate mechanic,
dull-faced, drew a loop of cord from a box nearby, while Kashtanov
went through actions that seemed fantastic. He stooped, groped along
the floor, and then gripped what looked like thin air with his fingers
and lifted upwards. But it wasn't air, Chris knew; it was the
invisible body of a man--the man who had destroyed the ZX-2, the man
whom he had shot at in the cubby of the ZX-1--whose invisibility was
now to be stripped from him.

By what? Carefully Chris swivelled his gaze around until it caught on
an object which dwarfed Istafiev, now waiting by its side with one
hand on the small panel of a switchboard.

* * * * *

A strange thing, truly, to find in a little hut on Azuero Peninsula!
Row upon row of slender curved tubes, describing a three-quarter ovoid
so that there was an opening for entrance in front, rose to a height
of some eight feet, the whole topped by a curious glassy dome which
was filled with creamy substance. There was room inside the layers of
tubes for a man's body to stand upright--and a man's body was upright
in it now, held by cords strapped to his unseen arms.

Invisibility! The dream of scientists for years! Here created, here
taken away--by the simple manipulation of two levers on the control
panel.

Intently Chris watched Istafiev pull down the right-side lever.

As it came down, the creamy liquid in the dome above the cage began to
swirl slowly, then to froth and boil and whip round and round, while
thick, dropsical bubbles slid up from its heaving surface and burst,
discharging a kind of grayish mist, under which the white substance
sank, until there was nothing left in the dome but drab-colored vapor.
On the completion of this stage, the layers of tubes below warmed
into life. They glowed with a soft