"But how?" I asked helplessly.
In answer, he touched a button set in the wall, and motioned us to seat ourselves in the chairs beside the window. A green-robed servant entered, in a moment, with a metal cabinet. He handed this to Kethra, and then departed.
The cabinet was an oblong box of black metal, a yard or more in its greatest length. Our companion touched a stud in the floor with his sandaled foot, and a small square section of the floor sprang up on four legs, or supports, forming a little table. Setting the cabinet on this table, our friend opened it.
Inside was a small, gleaming apparatus, consisting of a squat little box on which was set a small horn like that of a radio loud-speaker, but much smaller. From the box a flexible cord led, splitting at its end into three separate cords, each of which was metal-tipped. Setting this on the table, Kethra then drew from the cabinet three or four small, shapeless objects, gray and withered and deeply wrinkled, smaller in size than a baseball, the nature of which I could not guess.
He turned to us, now. "This mechanism," he said, indicating the gleaming apparatus, "is what we call a brain-reader. As you know, the brain preserves in its convolutions an indelible, unchangeable record of every word and action. When we remember a thing, we simply refer to that record, which we call memory, but which is in reality a very tiny change, but a lasting one. And this apparatus, when connected to a human brain by way of the nervous system, reads, from the myriad convolutions of that brain, the record of memory which is stamped on those convolutions."
With a swift movement, he fastened three clamps of metal to his body, one above the forehead, one around the neck, and the other along his spine. "These clamps make direct contact to the nervous system, through the skin," he explained, "and to them I attach the three cords from the brain-reader," suiting the action to the word. This done, he snapped a switch in the little box beneath the horn, and at once a nasal, metallic voice began to speak from that horn, in the Kanlar tongue.
Kethra's own voice came to us above the twanging one from the brain-reader. "It is giving a record of my experiences within the last few hours," he explained, "and will go back farther and farther as it continues, back to my very first memory, if allowed to run. Or I can use it to concentrate on any given period of my own life, and it will read with unvarying accuracy the impressions and sensations of my brain during that period. A mechanical, perfect memory," and he snapped off the switch and removed the clamps from his body.
"Nor does its usefulness stop there," he added, while we stared dumfoundedly at the little mechanism. "Here," he went on, picking up one of the withered gray objects, "is a human brain, the brain of one of the great men of our people, who died five centuries ago. And yet every memory and every thought and sensation in his life, imprinted unchangeably on his brain, is available to us by using the brain-reader."
He rapidly fitted over the withered brain a hollow hemisphere of metal, and attached to it the cords from the apparatus. A snap of the switch, and again the same nasal voice broke the silence, from the horn, speaking in the Kanlar tongue, and reading steadily on from the brain it was connected with, reciting the inmost thoughts and ideas and aspirations of a man dead for five hundred years. I shuddered, involuntarily, and Kethra snapped off the apparatus.