-this second frequency was found after
thousands of trials and is, I believe, the exact frequency existing in
the optic nerves themselves--and sent to the receiving headset.
Modulated as it is, and producing a three-dimensional picture, after
rectification in the receiver, it reproduces exactly what has been
'viewed,' if due allowance has been made for the size and configuration
of the different brains involved in the transfer. You remember a sort of
flash--a sensation of seeing something--when the educator worked on
you? Well, you did see it, just as though it had been transmitted to the
brain by the optic nerve, but everything came at once, so the impression
of sight was confused. The result in the brain, however, was clear and
permanent. The only drawback is that you haven't the visual memory of
what you have learned, and that sometimes makes it hard to use your
knowledge. You don't know whether you know anything about a certain
subject or not until after you go digging around in your brain looking
for it."

"I see," said Crane, and Dorothy, the irrepressible, put in:

"Just as clear as so much mud. What are the improvements you added to
the original design?"

"Well, you see, I had a big advantage in knowing that cerebrin was the
substance involved, and with that knowledge I could carry matters
considerably farther than Dunark could in his original model. I can
transfer the thoughts of somebody else to a third party or to a record.
Dunark's machine couldn't work against resistance--if the subject wasn't
willing to give up his thoughts he couldn't get them. This one can take
them away by force. In fact, by increasing plate and grid voltages in
the amplifier, I can pretty nearly burn out a man's brain. Yesterday, I
was playing with it, transferring a section of my own brain to a
magnetized tape--for a permanent record, you know--and found out that
above certain rather low voltages it becomes a form of torture that
would make the best efforts of the old Inquisition seem like a petting
party."

"Did you succeed in the transfer?" Crane was intensely interested.

"Sure. Push the button for Shiro, and we'll start something."

"Put your head against this screen," he directed when Shiro had come in,
smiling and bowing as usual. "I've got to caliper your brains to do a
good job."

The calipering done, he adjusted various dials and clamped the
electrodes over his own head and over the heads of Crane and Shiro.

"Want