Suddenly the young inventor looked up at his father with a glow of triumph.

“Dad, I just got a reaction to my sense-of-touch experiment!”

CHAPTER XVII

AN URGENT WARNING

Mr. Swift looked on eagerly as Tom explained and demonstrated his touch apparatus.  By moving a pantograph control, Tom was able to manipulate the claws like a hand with fingers.  Whenever they touched any material, the brain gauges instantly registered an electrical reaction inside the sphere.

The swing of a voltmeter needle showed how firmly the substance resisted the claw’s touch, thus indicating its hardness or softness.

“With a computer device, such as we planted in Exman,” Tom went on, “the brain would also be able to assimilate the textural pattern of any substance.”

“Wonderful, son!” Mr. Swift exclaimed.  “I hope I can do as well with this artificial sense of sight I’m working on.”

Another hour went by before Mr. Swift was ready to test his own arrangement.

“You’ve probably heard of the experiments conducted with blind persons,” he told Tom.  “By stimulating the right part of their brain with a lead from a cathode-ray-tube device, an awareness of light and dark can be restored.”

Tom nodded.

“Well, I’m using the same principle,” Mr. Swift went on, “but with a sort of television camera scanning setup.”

He asked Tom to draw the drapes and shut off the room lights, throwing the laboratory into complete darkness, except for the weirdly glowing “brain” in the glass sphere.  Then Mr. Swift shone a flashlight at the scanner.  The brain responded by glowing more brightly itself!

Next, after the drapes were opened again and the overhead fluorescent lights switched on, Mr. Swift painted a pattern of black-and-white stripes on a large piece of cardboard.  He held this up to the scanner.

Visible ripples of brightness and less-brightness passed through the glowing ball of energy inside the sphere.  It was reproducing the striped pattern!

“Dad, that’s amazing!” Tom said with real admiration.

Mr. Swift shook his head.  “Pretty crude, I’m afraid.  The brain energy by itself can’t take the place of a picture tube in a TV receiver.  What we need is an analog computer to sum up the scanning pattern picked up by the camera tube and then pass this information along in code form.”

Before Tom could comment, the alarm bell rang on the electronic brain.  The Swifts dropped everything and rushed to the machine.

“Wonder if it’s Exman?” Tom exclaimed.

The answer was quickly revealed as the keys began punching out the incoming message on tape.  At the same time, a flow of strange mathematical symbols flashed, one after another, on the lighted oscilloscope screen mounted above the keyboard.

Tom and his father read the tape as it unreeled.