"Professor!" cried the Director, rushing to meet their guest and lecturer as the door was thrown open, and the great man appeared, calm and composed, as if there was nothing more in the wind than an ordinary Scientific Discourse. "You are always welcome, my friend, always welcome"-the two enthusiasts for science wrung hands-"and never more welcome than tonight. Then the great mystery is to be solved at last. The Theatre is crammed with people. What does it mean? You must tell me before you go in."The Physicist smiled."I came to a conviction that I was on the true line five years ago," he said. "It is only within the last six months that I have demonstrated the thing to a certainty. I will tell you, my friend," he whispered, "before we go in."Then he advanced and shook hands with the President."Whatever the importance of your Discovery, Professor," said the President, "we are fully sensible of the honor you have done us in bringing it before an English audience first of all, and especially before an audience of the Royal Institution."