His life as child, boy, and man has revealed the born investigator with original reasoning powers, unlimited imagination, and daring method. It is not surprising, therefore, that a man of this kind should exhibit a ceaseless, absorbing desire for knowledge, willing to spend his last cent in experimentation to satisfy the cravings of an inquiring mind.
There is nothing of the slap-dash style in Edison's experiments. While he "tries everything," it is not merely the mixing of a little of this, some of that, and a few drops of the other, in the hope that something will come of it. On the contrary, his instructions are always clear-cut and direct, and must be followed out systematically, exactly, and minutely, no matter where they lead nor how long the experiment may take.
Unthinking persons have had a notion that some of Edison's successes have been due to mere dumb fool luck—to fortunate "happenings." Nothing could be farther from the truth, for, on the contrary, it is owing almost entirely to his comprehensive knowledge, the breadth of his conception, the daring originality of his methods, and minuteness and extent of experiment, combined with patient, unceasing perseverance, that new arts have been created and additions made to others already in existence.
One of the first things Edison does in beginning a new line of investigation is to master the literature of the subject. He wants to know what has been done before. Not that he considers this as final, for he often obtains vastly different results by repeating in his own way the experiments of others.
"Edison can travel along a well-used road and still find virgin soil," remarked one of his experimenters recently, who had been trying to make a certain compound, but with poor success. Edison tried it in the same way, but made a change in one of the operations and succeeded.
Another of the experimental staff says: "Edison is never hindered by theory, but resorts to actual experiment for proof. For instance, when he conceived the idea of pouring a complete concrete house it was universally held that it would be impossible because the pieces of stone in the mixture would not rise to the level of the pouring-point, but would gravitate to a lower plane in the soft cement. This, however, did not hinder him from making a series of experiments which resulted in an invention that proved conclusively the contrary."
Having conceived some new idea and read everything obtainable relating to the subject in general, Edison's fertility of resource and originality come into play. He will write in one of the laboratory note-books a memorandum of the experiments to be tried, and, if necessary, will illustrate by sketches.
This book is then given to one of the large staff of experimenters. Here strenuousness and a prompt carrying on of the work are required. The results of each experiment must be recorded in the notebook, and daily or more frequent reports are expected. Edison does not forget what is going on, but in his daily tours through the laboratory keeps in touch with the work of all the experimenters. His memory is so keen and retentive that he is as fully aware of the progress and details of each of the numerous experiments constantly going on as if he had made them all himself.
The use of laboratory note-books was begun early in the Menlo Park days and has continued ever since. They are plain blank-books, each about eight and a half by six inches, containing about two hundred pages. At the present time there are more than one thousand of these books in the series. On their pages are noted Edison's ideas, sketches, and memoranda, together with records of countless thousands of experiments made by him or under his direction during more than thirty years.
These two hundred thousand or more pages cover investigations into every department of science, showing the operations of a master mind seeking to surprise Nature into a betrayal of her secrets by asking her the same question in a hundred different ways. The breadth of thought, thoroughness of method, infinite detail, and minuteness of investigation proceeding from the workings of one mind would surpass belief were they not shown by this wonderful collection of note-books.