From the April 10, 1937, issue


Pearls are the gift of water; we prize their drop-round perfection of shape, their softly gleaming luster. Gift of water also are the round, lustrous, pearly globes shown on the front cover of this number of the Science News Letter. But they are living pearls; eggs of trout that will presently be broken to release the promise of pleasure to sportsmen of the summers of the 1940s.


A startling new clue to the puzzling structure of the nucleus of the atom was revealed to scientists at Harvard University’s Cruft Laboratory by Dr. J.D. Cockcroft, distinguished British physicist.

The clue was contained in an experiment Dr. Cockcroft and his associates recently completed at the Cavendish Laboratory, Cambridge, England, the first ever conducted in which the emission of heavy particles has been detected from an artificially produced radioactive substance.

Particularly impressive was Dr. Cockcroft’s unexpected finding that these heavy particles possessed a continuous energy distribution, something never previously discovered in reactions of this type.

Dr. Cockcroft’s experiments concerned the disintegration of radio-lithium, an artificially radioactive substance produced by bombarding a lithium isotope of mass seven with nuclei of heavy hydrogen atoms, an accepted experimental procedure in science’s attempts to unravel the secrets of the atom.

Not expected, however, was Dr. Cockcroft’s finding that “this radio-lithium breaks up apparently not into stable beryllium of mass eight but in general into a beryllium with a surplus of energy—an excited beryllium eight nucleus.

“This nucleus,” he declared, “subsequently breaks up into two beryllium nuclei which may each have as much as 6 million volts of energy but in general have less.” These are the unexpected heavy particles.

The implications or theoretical explanations of the discovery are not yet clear, although it is expected eventually to be of considerable significance. Dr. Cockcroft believes “it may be necessary to assume that the beryllium nucleus of mass eight can exist in one or another of such excited states.”