From the January 7, 1933, issue

ATOM BUILDING KEEPS STARS SHINING, SAYS A.A.A.S. HEAD

The building up of other heavier atoms out of hydrogen stokes the internal heat of the stars, including the sun, Prof. Henry Norris Russell, Princeton University astronomer recently elected president of the American Association for the Advancement of Science, suggested in the Maiben lecture before the Association.

The hardest problem of all star study is the source of the energy that keeps the stars shining, he explained. Synthesis and annihilation of atoms are the only two processes so far suggested that would supply enough heat to last for the millions of years of geological time.

Present theories indicate that the mutual annihilation of the positive and negative particles, the protons and the electrons, would not happen except at temperatures of many billions of degrees such as do not exist within the stars.

Prof. Russells provisional theory is therefore that atomic synthesis makes the sun and stars give off heat and light.

MILLIKAN AND COMPTON DEBATE COSMIC-RAY FACTS AND THEORIES

Two of Americas leading physicists, both Nobelists, discussed facts and theories about cosmic rays before the American Association for the Advancement of Science.

About most of the experimental facts, they agreed. About the deductions from thousands of experiments performed by scores of investigators ranging the world, they largely disagreed.

Dr. Robert A. Millikan of California Institute of Technology upheld strongly as a fact his conclusion that the cosmic rays that enter Earths atmosphere are photons, like X rays and gamma radiations of the same family as light and heat.

Dr. A.H. Compton of the University of Chicago found no way of reconciling the data with the hypothesis that any considerable portion of the cosmic rays consists of photons. He concludes that cosmic rays come from outer space as high-speed electrified particles, either negatively charged electrons or positively charged protons.

As to what causes the discharging of the sensitive electrical instruments used in detecting the effects of cosmic radiation, Drs. Compton and Millikan agree. Very energetic electrified particles produce the effect, but whereas Dr. Compton considers them the original rays, Dr. Millikan advanced evidence that they are secondary radiation produced in the Earths air by photons smashing into the hearts of air atoms.

GROWTH OF PLANTS STIMULATED BY PROPER X-RAY TREATMENT

X rays can cause plants to grow faster, blossom earlier, form more chlorophyll, and in general speed up their life processes. But if they get too much of a dose of the rays, they become cripples.

This in brief summary is what Prof. Charles A. Shull of the University of Chicago has found in experiments that he reported before the meeting of the American Society of Plant Physiologists.

Prof. Shull exposed corn, wheat, oats and sunflowers to X rays for periods of from 1 to 5 minutes inclusive, under screens to take out the harmful parts of the X-ray spectrum, and also for 10 minutes without the benefit of screening. He compared the growth of these plants with control plants that were not X-rayed at all.

All the rayed plants except the 10-minute lot were apparently stimulated by the treatment. In some cases they became juicier, or more succulent, as well as larger. In corn a considerable increase of the green food-making substance, chlorophyll, was noted, running from 20 to 60 percent above the controls. X-rayed seeds carried on their respiratory processes with greater energy, the data indicating from 30 to 50 percent increase.

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