“I sincerely hope it will,” declared Jules in good English. “We’re really getting rather rusty. I met Regnier yesterday out at Pré Catalan with Madame Sohet, and he hinted to me that some great mystery had arisen; but he would tell me nothing further.”

“Regnier, as head of the Service, is always well informed, and like an oyster,” Yvette remarked with a laugh. “So I suppose we must wait for something to happen. I hate to be idle.”

“Yes. Something will surely happen very shortly,” said Dick. “I have a curious intuition that we shall very soon be away again on another mission. My intuition never fails me.”

Dick Manton’s words were prophetic, for on that same evening before a meeting of the Royal Society in London, Professor Rudford, the world-famed scientist, made an amazing speech in which he said:

“Could we but solve the problem of releasing and controlling the mighty forces locked up in this piece of chalk, we should have power enough to drive the biggest liner to New York and back. We should have at our disposal energy unlimited. The daily work of the world would be reduced to a few minutes’ tending of automatic machinery. And, I may add, the first nation to solve that problem will have the entire world at its mercy. For no nation, or combination of nations, could stand even against a small people armed with force unlimited and terrible. And—gentlemen—we are on the way to solving that problem!”

As the words fell slowly and calmly from his lips his hearers felt a thrill of ungovernable emotion, almost of apprehension. For they knew well that he spoke only of what he knew, and the measured phrases conjured up in their keen brains not only a picture of a world where labour had been reduced to the vanishing point, but of a world where evil still strove with good, where the enemies of society still strove against the established order of things which they hated, where crime in the hands of the master criminal, armed with force whose potentiality they could only dream of, would be something transcending in sheer horror all the past experiences of tortured humanity.

Supposing the great secret fell into the wrong hands!

The speech at the Royal Society was a nine days’ wonder.

The unthinking Press made merry in the bare idea of a lump of chalk being a source of power. Then the transient impression faded as public attention returned to football and the latest prize-fight. But behind the scenes, in a hundred laboratories, students bent unceasingly over their myriad experiments, striving to wrest from Nature her greatest secret, the mystery of the mighty energy of the atom. Since the day when Madame Curie had discovered that in breaking up, yet seemingly never growing less, radium was shooting off day and night power which never seemed to diminish, the minds of the men of science had been filled with the dream of discovering the secret.

Could they learn to accelerate the process? Could they induce radium to deliver in a few moments the power which, expending itself for centuries untold, never seemed to grow less? Could they learn to control it, or would it, when at last the secret was discovered, prove to be a Frankenstein monster of titanic power, wreaking untold destruction on the world?