Science: Atoms, Drugs, Wines

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To St. Louis, busy mart, came 1,500 chemists for the 75th meeting of the American Chemical Society; organic chemists, inorganic chemists, biological chemists, physical chemists, industrial chemists, engineering chemists; chemists who worked with spectroscope and vacuum tube to find out the structure of the atom, chemists who spent their days with rabbit and guinea pig to ferret out the secrets of growth, chemists who messed about with saps and sawdust to build up substitutes for rubber, sugar, silk. More than 300 scientific papers were read. More than a fifth of these were on the program of the Division of Physical and Inorganic Chemistry, the longest program of any of the 16 divisions. This division united with the Organic Division to give a symposium on "Atomic Structure and Valence," officially announced as "probably the most notable in this sphere of pure science ever held in the United States."

Reeling Atoms. Probably the most notable paper at this "most notable symposium" was the report of Professor William Draper Harkins, University of Chicago chemist. Fourteen years ago C. T. R. Wilson discovered that atoms shot at high speed through a gas, may be made to leave visible trails. Since then Professor Harkins has been trailing helium atoms. He has been busily exploding chunks of "thorium C" and other radioactive substances which shoot off atoms at the mad speed of 12,000 miles per second.

"Stepping up" his movie machine, he has taken reels of the reeling helium atoms; his picture gallery now consists of 100,000 photographs showing the tracks of about 1,000,000 atoms. The atomic trail is infinitesimal, a narrow path (usually straight but sometimes bent as though the atom had trespassed too close to some minute object which had repelled it) made of the same water vapor that forms the clouds. Occasionally some dizzily dashing helium atom hurtling through the hundreds of thousands of normal atomic citizens in the air crashes kerplunk into the nucleus of one of them. Only 30 such collisions occurred in all the 1,000,000 trails recorded by Professor Harkins.

The shock of a helium nucleus crashing into the nucleus of a nitrogen atom causes an explosion which disintegrates the atom. Out of the wreck a new fluorine atom emerges, but not for long. It explodes immediately, shooting off a furiously fast atom of hydrogen and a slower atom of a new kind of oxygen which is heavier than either the helium or the nitrogen atom. According to Einstein's theory, when helium is formed from lighter hydrogen atoms, energy is given off (enough to heat an ordinary house from 500 to 1 ,000 years in the formation of one pound of helium atoms).

This was the energy that Millikan demonstrated in the cosmic ray (TIME, March 26). But the helium-nitrogen activity seems to be just the opposite. When helium and nitrogen collide and explode, forming oxygen and hydrogen, energy appears to be stored rather than given off. From this have arisen arguments which support the theory of Prof. Thomas Chrowder Chamberlin—that the earth has been built up by the aggregation of smaller bodies such as meteorites or planetesimals, in which energy has been stored.