ientific bump certainly shows no sign of weakness. He
might even be some new type of kleptomaniac. He steals things, and he
has already stolen far more than any man could ever have any need of,
and he leaves in its place a 'stock' certificate in his own company. He
is not violent, for hasn't he carefully warned the men not to use the
C-32L mask? You'll remember his careful instructions as to how to revive
the people!

"He has developed this machine for invisibility, and naturally he can
fly in and out of the air guard, without their knowing he's there,
provided their microphonic detectors don't locate him. I believe he uses
some form of glider. He can't use an internal combustion engine, for the
explosions in the cylinders would be as visible as though the cylinders
were made of clear quartz. He cannot have an electric motor, for the
storage cells would weigh too much. Furthermore, if he were using any
sort of prop, or a jet engine, the noise would give him away. If he used
a glider, the noise of the big plane so near would be more than enough
to kill the slight sounds. The glider could hang above the ship, then
dive down upon it as it passed beneath. He has a very simple system of
anchoring the thing, as I discovered to my sorrow. It's a powerful
electro-magnet which he turns on when he lands. The landing deck of the
big plane was right above our office aboard, and I found my watch was
doing all sorts of antics today. It lost an hour this morning, and this
afternoon it gained two. I found it was very highly magnetized--I could
pick up needles with the balance wheel. I demagnetized it; now it runs
all right.

"But to get back, he anchors his ship, then, leaving it invisible, he
goes to the air lock, and enters. He wears a high altitude suit, and on
his back he has a portable invisibility set and the fuel for his torch.
The gas has already put everyone to sleep, so he goes into the ship,
still invisible, and melts open the safe.

"His power supply for the invisibility machine seems to be somewhat of a
problem, but I think I would use a cylinder of liquid air, and have a
small air turbine to run a high voltage generator. He probably uses the
same system on a larger scale to run his big machine on the ship. He
can't use an engine for that either.

"That torch of his is interesting, too. We have had atomic hydrogen
welding for some time, and atomic hydrogen releases some 100,000
calories per mole of molecular hydrogen;