WHILE the world's progress depends largely upon their ingenuity, inventors are not usually persons who have adopted invention as a distinct profession, but, generally speaking, are otherwise engaged in various walks of life. By reason of more or less inherent native genius they either make improvements along lines of present occupation, or else evolve new methods and means of accomplishing results in fields for which they may have personal predilections.

Now and then, however, there arises a man so greatly endowed with natural powers and originality that the creative faculty within him is too strong to endure the humdrum routine of affairs, and manifests itself in a life devoted entirely to the evolution of methods and devices calculated to further the world's welfare. In other words, he becomes an inventor by profession. Such a man is Edison. Notwithstanding the fact that nearly forty years ago (not a great while after he had emerged from the ranks of peripatetic telegraph operators) he was the owner of a large and profitable business as a manufacturer of the telegraphic apparatus invented by him, the call of his nature was too strong to allow of profits being laid away in the bank to accumulate. As he himself has said, he has "too sanguine a temperament to allow money to stay in solitary confinement." Hence, all superfluous cash was devoted to experimentation. In the course of years he grew more and more impatient of the shackles that bound him to business routine, and, realizing the powers within him, he drew away gradually from purely manufacturing occupations, determining deliberately to devote his life to inventive work, and to depend upon its results as a means of subsistence.

All persons who make inventions will necessarily be more or less original in character, but to the man who chooses to become an inventor by profession must be conceded a mind more than ordinarily replete with virility and originality. That these qualities in Edison are superabundant is well known to all who have worked with him, and, indeed, are apparent to every one from his multiplied achievements within the period of one generation.

If one were allowed only two words with which to describe Edison, it is doubtful whether a close examination of the entire dictionary would disclose any others more suitable than "experimenter--inventor." These would express the overruling characteristics of his eventful career. It is as an "inventor" that he sets himself down in the membership list of the American Institute of Electrical Engineers. To attempt the strict placing of these words in relation to each other (except alphabetically) would be equal to an endeavor to solve the old problem as to which came first, the egg or the chicken; for although all his inventions have been evolved through experiment, many of his notable experiments have called forth the exercise of highly inventive faculties in their very inception. Investigation and experiment have been a consuming passion, an impelling force from within, as it were, from his petticoat days when he collected goose-eggs and tried to hatch them out by sitting over them himself. One might be inclined to dismiss this trivial incident smilingly, as a mere childish, thoughtless prank, had not subsequent development as a child, boy, and man revealed a born investigator with original reasoning powers that, disdaining crooks and bends, always aimed at the centre, and, like the flight of the bee, were accurate and direct.

It is not surprising, therefore, that a man of this kind should exhibit a ceaseless, absorbing desire for knowledge, and an apparently uncontrollable tendency to experiment on every possible occasion, even though his last cent were spent in thus satisfying the insatiate cravings of an inquiring mind.

During Edison's immature years, when he was flitting about from place to place as a telegraph operator, his experimentation was of a desultory, hand-to-mouth character, although it was always notable for originality, as expressed in a number of minor useful devices produced during this period. Small wonder, then, that at the end of these wanderings, when he had found a place to "rest the sole of his foot," he established a laboratory in which to carry on his researches in a more methodical and practical manner. In this was the beginning of the work which has since made such a profound impression on contemporary life.

There is nothing of the helter-skelter, slap-dash style in Edison's experiments. Although all the laboratory experimenters agree in the opinion that 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. Nor is the spirit of the laboratory work represented in the following dialogue overheard between two alleged carpenters picked up at random to help on a hurry job.

"How near does she fit, Mike?"

"About an inch."

"Nail her!"

A most casual examination of any of the laboratory records will reveal evidence of the minutest exactitude insisted on in the conduct of experiments, irrespective of the length of time they occupied. Edison's instructions, always clear cut and direct, followed by his keen oversight, admit of nothing less than implicit observance in all details, no matter where they may lead, and impel to the utmost minuteness and accuracy.

To some extent there has been a popular notion that many of Edison's successes have been due to mere dumb fool luck--to blind, fortuitous "happenings." Nothing could be further from the truth, for, on the contrary, it is owing almost entirely to the comprehensive scope of his knowledge, the breadth of his conception, the daring originality of his methods, and minuteness and extent of experiment, com- bined with unwavering pertinacity, that new arts have been created and additions made to others already in existence. Indeed, without this tireless minutiae, and methodical, searching spirit, it would have been practically impossible to have produced many of the most important of these inventions.

Needless to say, mastery of its literature is regarded by him as a most important preliminary in taking up any line of investigation. What others may have done, bearing directly or collaterally on the subject, in print, is carefully considered and sifted to the point of exhaustion. Not that he takes it for granted that the conclusions are correct, for he frequently obtains vastly different results by repeating in his own way experiments made by others as detailed in books.

"Edison can travel along a well-used road and still find virgin soil," remarked recently one of his most practical experimenters, who had been working along a certain line without attaining the desired result. "He wanted to get a particular compound having definite qualities, and I had tried in all sorts of ways to produce it but with only partial success. He was confident that it could be done, and said he would try it himself. In doing so he followed the same path in which I had travelled, but, by making an undreamed-of change in one of the operations, succeeded in producing a compound that virtually came up to his specifications. It is not the only time I have known this sort of thing to happen."

In speaking of Edison's method of experimenting, another of his laboratory staff says: "He 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."