two grains of gas give one
hundred thousand calories. Oxygen has not been prepared in any
commercial quantity in the atomic state. From watching that man's torch,
from the color of the flame and other indications, I gather that he uses
a flame of atomic oxygen-atomic hydrogen for melting, and surrounds it
with a preheating jacket of atomic hydrogen. The center flame probably
develops a temperature of some 4000 deg. centigrade, and will naturally make
that tungsten alloy run like water.

"As to the machine here--it is, as I said, a machine which impresses
very high frequencies on the body it is connected with. This puts the
molecules in vibration at a frequency approaching that of light, and
when the light impinges upon it, it can pass through readily. You know
that metals transmit light for short distances, but in order that the
light pass, the molecules of metal must be set in harmonic vibration at
a rate approaching the frequency of light. If we can impress such a
vibration on a piece of matter, it will then transmit light very freely.
If we impress this vibration on the matter, say the body, electrically,
we get the same effect and the body becomes perfectly transparent. Now,
since it is the vibration of the molecules that makes the light pass
through the material, it must be stopped if we wish to see the machine.
Obviously it is much easier to detect me here among solid surroundings,
than in the plane high in the sky. What chance has one to detect a
machine that is perfectly transparent when there is nothing but
perfectly transparent air around it? It is a curious property of this
vibrational system of invisibility that the index of refraction is made
very low. It is not the same as that of air, but the difference is so
slight that it is practically within the limits of observation error; so
small is the difference that there is no 'rainbow' effect. The
difference of temperature of the air would give equal effect.

"Now, since this vibration is induced by radio impulse, is it not
possible to impress another, opposing radio impulse, that will overcome
this tendency and bring the invisible object into the field of the
visible once more? It is; and this machine on the table is designed to
do exactly that. It is practically a beam radio set, projecting a beam
of a wavelength that alone would tend to produce invisibility. But in
this case it will make me visible. I'm going to stand right here, and
Bob can operate that s