Giant brains; or, Machines that think

by Edmund Callis Berkeley

Fig. 2. Tape reels.

Think of the enormous files in libraries, government, and business. Think of the problems of space and cost and access which these files imply. We can then see that this new development may well be of extraordinary importance.

Mercury Tanks

Fig. 3. Mercury tank.

Scientists are investigating other storage devices having still more remarkable properties, but these have the disadvantage that, when the power goes off, the information vanishes. One of these new storage devices is called a mercury tank ([see Fig. 3]). It consists mainly of a section of iron or steel pipe filled with mercury. At each end of this pipe, touching the mercury, is a thin slab of a crystal of quartz. Quartz, which is a common stone, and which nearly all sand is made of, changes its shape when pulsed with electricity. We put a pattern of electrical pulses into the quartz slab at one end of the mercury tank; for example, we could have the pattern 1101 meaning “pulse, pulse, no pulse, pulse.” The electrical pulses going into the quartz slab make the quartz vibrate. Thus ripples are produced in the mercury, and waves in the pattern 1101 meaning “wave, wave, no wave, wave” travel down the tank and strike the quartz slab at the far end. The quartz slab there changes its shape in the rhythm 1101, and it converts the waves back into electrical pulses in the same pattern. Then we take the pulses out of the far end along a wire, make them stronger again with an amplifier, give them the right form again, and feed them back into the front end of the mercury tank. The mercury tank is a clever use of the principle of an echo, as when you call across a valley and the rocks answer you back. We can store a pattern of 400 pulses (each a unit of information, a 1 or a 0, and each a millionth of a second in duration), in a mercury tank about 20 inches long. A mercury tank and an echo are examples of delay lines—“lines” along which waves are “delayed.”

Electrostatic Storage Tube

Another of the memory devices being developed is called an electrostatic storage tube ([see Fig. 4]). This is a big electronic tube with a screen across one end. The screen may be of two layers: one of copper, which conducts electricity, and one of mica, a material that does not. In the other end of the tube is a beam of electrons, which we can turn on and off and shoot at any of 2 or 3 thousand specific points or spots on the screen.

Fig. 4. Electrostatic storage tube.