Three years passed, and Marvin was in the high school without having blown his eyes out. He was distinctly tamer now, though still afflicted with excess of leisure because his mathematics cost him so little. He always had time for sports, and the boy of fifteen was madly fond of dancing.

That summer his father took him on a long prospecting trip in the wilds of Canada and watched him develop into young manhood. Every morning they had their swim together in the pellucid purity of some lake rarely seen by the eyes of white men. All day long they searched ravine and gully, moving slowly from east to west across the continental formation. Every night they lay by the camp-fire and talked about many things, sometimes about the future. It was agreed that Marvin should be a chemist, but Chase kept drilling it in that early specialization was bad. He had suffered from it all his life, and wanted his boy to go slow.

Near the end of the trip the mining engineer slipped in crossing a slope of rock, and fell. When he arose, his right hand was so useless and painful that he suspected some bones had been broken. The first thing he did on reaching Chicago was to proceed to the hospital and have the swollen hand radiographed. One bone was found to be split, and the sufferer was led to another room that the hand might be immobilized.

Thus left alone with the X-ray man, Marvin plied him with questions. He so fascinated the radiographer that presently he was rewarded with a mystery even greater than that of the subtle unseen light. He was taken into a dark closet and permitted to peer into a small instrument containing salts of radium.

He saw a flight of stars, a sheaf of rays, a faint fierce sparkling! The heavy metallic radium atom was exploding! It was bombarding a small black screen with cannon flashes!

Instantly the boy inquired why somebody did not capture the power of that explosion and set it to work. He was told that any such achievement was impossible. The show was not affected by heat or cold, and would continue for a thousand years or more till the radium was all used up.

What were those flashes? How could he learn more about them? He must wait till he had enough physics to follow the writings of a man named Rutherford.

He was sorry to wait, but he was glad that some human being was at work on the job. He went home full of wonder and impatience. He never forgot the marvelous show. All through the year he kept seeing those immortal fireflies charging the darkness and wasting energy. He no longer broke the law by helping his mates with their mathematics, but spent extra time each day in reading mathematics beyond the requirements.

And so his high-school years went by. Athletics and girls, Latin and French and German went far to divert his mind from the mysteries of radium.

It was not until 1911, when he was about to graduate and enter Yale, that he ran on an article by the mysterious Rutherford and found himself able to understand some of it.

He had long since learned that even solid iron is full of spaces, and that within the spaces are minute particles in constant motion. He was now to learn that the minute particles are themselves hollow—that an atom is a central nucleus of positive electricity which holds in its sky one or more moons of negative electricity.

In other words, the cheek of a girl, which feels so smooth to the lips, is really a starry sky full of electric suns and moons. The tension between each sun and its moons is all that keeps the cheek from exploding when you kiss it. And here he had been calling them all “darlin’”! Well, he might have known that girls were composed of electricity. He had often felt it thrilling up his arm.

An atom of hydrogen was one charge of positive electricity balanced by one charge of negative. At least, he guessed that if you could ever get a hydrogen atom off by itself, it could be called a balance. But it was not a perfect balance, for the touch of fire would make the moon slip off and combine with the moons of oxygen in a sharp explosion.

An atom of helium was heavier, as if four positive charges were balanced by four negatives. Rutherford did not tell the young mind just how those four positive charges—which would naturally fly apart—were cemented into the nucleus, but Marvin guessed that two of the negatives did the work, leaving two moons in the sky. This balance was very strong. The gas never burns or explodes, and can be pressed into a liquid so cold that it boils far below the point where mercury freezes.

A girl composed entirely of helium would be perfectly neutral, incapable of sending out one flash or thrill. All the girls he knew were composed of flesh and blood, which of course were chemical substances but very far from neutral.

Now at last he understood what those flashes of light from the radium had been and still were, for the bombardment was steadily going on there in the dark corner of the hospital. They were the reflection of helium atoms that had lost two moons and came shooting out of the radium to find them. They would pick up the two missing satellites and again become the quiet inert gas. What bully stuff to put in a balloon, if only there were enough of it!

He wondered just how much electricity lay packed in the nucleus of a radium atom. The nucleus of every atom evidently carried a charge, an excess of positive over negative. He used to go up into the den, from which his father was generally absent, and think about it. He would pick up that old sieve of phosphor bronze and tilt it to an angle of thirty degrees and look at the minerals in the cabinet. If he could only get a spectrum from the positive electricity concealed in the heart of each atom, he could number the elements from hydrogen up. Just now they went by weights, but ought not cobalt to come before nickel, even if it was heavier? Cobalt was more like iron, and ought to come right after iron.