Man, the Sun & Seaweed

Scientists have searched for a means of turning heat directly into electric current since a series of experiments in the 1880s showed that a heated metal plate will "boil off" clouds of electrons. Reason: an electric current is simply a flow of electrons. Last week, before the 124th meeting of the American Association for the Advancement of Science, General Electric announced that it had turned the trick. The device that may change the world's means of making power: a small "thermionic converter" that now turns about 9% of its heat energy into electricity, may eventually convert up to 30%.

The converter is made of two plates of tungsten that are a fraction of a millimeter apart. Between them is a vapor in near vacuum. The plates are so treated that they have different electric potentials. (G.E. will disclose neither the vapor nor the method of treating the plates.) The plate with the higher potential is heated to about 1,500DEG centigrade, the other to around 1,000DEG centigrade. The first plate is hot enough to release electrons; the second is not. Clouds of electrons boil off the hotter plate (the cathode) and are attracted to the cooler plate (the anode), thereby producing a current of electricity strong enough to light a small bulb. In effect, the device is a simple battery, energized by heat.

One great advantage of the system: it can use heat from any source. Eventually, it may be possible to convert the sun's heat directly into electricity, power spaceships by solar energy. Says Dr. Guy Suits, G.E. vice president and director of research: "Right now we think our converter is significant to science. If we can increase its efficiency, it will be fundamentally significant to technology."

Other items at the A.A.A.S. meeting:

P: The simplest way to cut the physical and mental strain of space flight may be to make the crew unconscious, suggested Dr. John Lyman, U.C.L.A. associate professor of engineering and psychology. For most of the flight, he said, spacemen could be knocked out by drugs or low temperatures. They could be fed intravenously. To solve some of the same problems, Psychologist Donald Michael said that withdrawn personalities like schizophrenics or hermits might make fine spacemen, provided that they had the motivation to do their jobs. Eskimos or Buddhist monks might be good, too, because they come from "more sedentary, less timebound cultures than our own."

P: Man and his animal relatives are a "type of highly modified plant life," according to Biologist Lawrence S. Dillon of Texas A. & M. By examining the internal structures of living cells. Dillon concludes that all life evolved from microscopic blue-green algae. From these algae developed two main branches of life. One became what is commonly called the plant kingdom, the other evolved into brown seaweed and eventually produced man and his fellow animals. Said Dillon: "We are forced to conclude that all life belongs to only one kingdom, which in all honesty must be recognized as the kingdom of plants."

P: Fearful that the U.S. missile-satellite effort may cause other sciences to be neglected, Du Pont President Crawford H. Greenewalt warned that "hasty expedients may, while promising immediate advantage, weaken rather than advance our long-range scientific endeavor." Said he: "I sincerely hope that no scientific chauvinism will lead us down ill-considered pathways toward goals which may be more glitter than gold."

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