iting as he talked.

"For any given frequency, _f_, and phase angle, _theta_, you integrate,
between limits zero and _pi_ divided by two, sine theta d...."

"Hold it--I'm sinking!" Nadia exclaimed. "I don't integrate at all
unless it is absolutely necessary. As long as you stick to general
science, I'm right on your heels, but please lay off of integrations
and all that--most especially stay away from those terrible electrical
integrations. I always did think that they were the most poisonous kind
known. I want only a general idea--that's all that I can understand,
anyway."

"Sure, I forgot--guess I was getting in deeper than is necessary,
especially since this whole thing of beam transmission is pretty crude
yet and is bound to change a lot before long. There is so much loss
that when we get more than a few hundred million kilometers away from
a power-plant we lose reception entirely. But to get going again,
the receptors receive the beam and from them the power is sent to the
accumulators, where it is stored. These accumulators are an outgrowth
of the storage battery. The theory of the accumulator is...."

"Lay off the theory, please!" the listener interrupted. "I understand
perfectly without it. Energy is stored in the accumulators--you put it
in and take it out. That's all that is necessary."

* * * * *

"I'd like to give you some of the theory--but, after all, it wouldn't
add much to your understanding of the working of things, and it might
mix you up, as some of it is pretty deep stuff. Then, too, it would
take a lot of time, and the rest of your friends would squawk if I
kept you here indefinitely. From the accumulators, then, the power
is fed to the converters, each of which is backed by a projector.
The converters simply change the aspect of the rays, from the
energy aspect to the material aspect. As soon as this is done, the
highly-charged particles--or whatever they are--thus formed are
repelled by the terrific stationary force maintained in the projector
backing the converter. Each particle departs with a velocity supposed
to be that of light, and the recoil upon the projector drives the
vessel, or car, or whatever it is attached to. Still with me?"

"Struggling a little, but my nose is still above the surface. These
particles, being so infinitesimally small that they cannot even be
detected, go right through any substance without any effect--they are
not even harmful."