Perhaps there has never been a man whose thoughts were so continually asking the question why as Thomas Alva Edison. Certainly there has never been one who has found the answer to that question in so many lines of scientific study. He has not merely happened on his discoveries. He has not been as much interested in the result as in the reasons for it. He belongs to the experimenting age. Once on a time men took the facts of nature for granted. But if they had always done so there would have been no telegraph, no telephone, no electric light, no phonograph. Each of these were achieved by working on a definite problem, and in no haphazard way. The inventor has become a scientist and a mechanic, and no longer an amateur discoverer. Chance has much less to do with the winning of new knowledge than it once had. A visitor to Edison’s laboratory tells how he found him holding a vial of some liquid to the light. After a long look at it he put the vial down on the table, and resting his head in his hands, stared intently at it, as if he expected the vial to make some answer. Then he picked it up, shook it, and held it again to the light. The visitor introduced himself. Edison nodded toward the bottle. “Take a look at those filings,” said he. “See how curiously they settle when I shake the bottle. In alcohol they behave one way, but in oil in this way. Isn’t that the most curious thing you ever saw--better than a play at one of your city theatres, eh?” Again he shook the vial. “What I want to know is what they mean by it; and I’m going to find out.” There is the man, he wants to know “what they mean by it,” he continually asks the question why, he is the great experimenter among great inventors.