It should perhaps be noted at this point that a curious effect observed at the laboratory was shown in connection with Edison lamps at the Philadelphia Exhibition of 1884. It became known in scientific parlance as the "Edison effect," showing a curious current condition or discharge in the vacuum of the bulb. It has since been employed by Fleming in England and De Forest in this country, and others, as the basis for wireless-telegraph apparatus. It is in reality a minute rectifier of alternating current, and analogous to those which have since been made on a large scale.

When Roentgen came forward with his discovery of the new "X"-ray in 1895, Edison was ready for it, and took up experimentation with it on a large scale; some of his work being recorded in an article in the Century Magazine of May, 1896, where a great deal of data may be found. Edison says with regard to this work: "When the X-ray came up, I made the first fluoroscope, using tungstate of calcium. I also found that this tungstate could be put into a vacuum chamber of glass and fused to the inner walls of the chamber; and if the X-ray electrodes were let into the glass chamber and a proper vacuum was attained, you could get a fluorescent lamp of several candle-power. I started in to make a number of these lamps, but I soon found that the X-ray had affected poisonously my assistant, Mr. Dally, so that his hair came out and his flesh commenced to ulcerate. I then concluded it would not do, and that it would not be a very popular kind of light; so I dropped it.

"At the time I selected tungstate of calcium because it was so fluorescent, I set four men to making all kinds of chemical combinations, and thus collected upward of 8000 different crystals of various chemical combinations, discovering several hundred different substances which would fluoresce to the X-ray. So far little had come of X-ray work, but it added another letter to the scientific alphabet. I don't know any thing about radium, and I have lots of company." The Electrical Engineer of June 3, 1896, contains a photograph of Mr. Edison taken by the light of one of his fluorescent lamps. The same journal in its issue of April 1, 1896, shows an Edison fluoroscope in use by an observer, in the now familiar and universal form somewhat like a stereoscope. This apparatus as invented by Edison consists of a flaring box, curved at one end to fit closely over the forehead and eyes, while the other end of the box is closed by a paste-board cover. On the inside of this is spread a layer of tungstate of calcium. By placing the object to be observed, such as the hand, between the vacuum-tube and the fluorescent screen, the "shadow" is formed on the screen and can be observed at leisure. The apparatus has proved invaluable in surgery and has become an accepted part of the equipment of modern surgery. In 1896, at the Electrical Exhibition in the Grand Central Palace, New York City, given under the auspices of the National Electric Light Association, thousands and thousands of persons with the use of this apparatus in Edison's personal exhibit were enabled to see their own bones; and the resultant public sensation was great. Mr. Mallory tells a characteristic story of Edison's own share in the memorable exhibit: "The exhibit was announced for opening on Monday. On the preceding Friday all the apparatus, which included a large induction-coil, was shipped from Orange to New York, and on Saturday afternoon Edison, accompanied by Fred Ott, one of his assistants, and myself, went over to install it so as to have it ready for Monday morning. Had everything been normal, a few hours would have sufficed for completion of the work, but on coming to test the big coil, it was found to be absolutely out of commission, having been so seriously injured as to necessitate its entire rewinding. It being summer-time, all the machine shops were closed until Monday morning, and there were several miles of wire to be wound on the coil. Edison would not consider a postponement of the exhibition, so there was nothing to do but go to work and wind it by hand. We managed to find a lathe, but there was no power; so each of us, including Edison, took turns revolving the lathe by pulling on the belt, while the other two attended to the winding of the wire. We worked continuously all through that Saturday night and all day Sunday until evening, when we finished the job. I don't remember ever being conscious of more muscles in my life. I guess Edison was tired also, but he took it very philosophically." This was apparently the first public demonstration of the X-ray to the American public.

Edison's ore-separation work has been already fully described, but the story would hardly be complete without a reference to similar work in gold extraction, dating back to the Menlo Park days: "I got up a method," says Edison, "of separating placer gold by a dry process, in which I could work economically ore as lean as five cents of gold to the cubic yard. I had several car-loads of different placer sands sent to me and proved I could do it. Some parties hearing I had succeeded in doing such a thing went to work and got hold of what was known as the Ortiz mine grant, twelve miles from Santa Fe, New Mexico. This mine, according to the reports of several mining engineers made in the last forty years, was considered one of the richest placer deposits in the United States, and various schemes had been put forward to bring water from the mountains forty miles away to work those immense beds. The reports stated that the Mexicans had been panning gold for a hundred years out of these deposits.

"These parties now made arrangements with the stockholders or owners of the grant, and with me, to work the deposits by my process. As I had had some previous experience with the statements of mining men, I concluded I would just send down a small plant and prospect the field before putting up a large one. This I did, and I sent two of my assistants, whom I could trust, down to this place to erect the plant; and started to sink shafts fifty feet deep all over the area. We soon learned that the rich gravel, instead of being spread over an area of three by seven miles, and rich from the grass roots down, was spread over a space of about twenty-five acres, and that even this did not average more than ten cents to the cubic yard. The whole placer would not give more than one and one-quarter cents per cubic yard. As my business arrangements had not been very perfectly made, I lost the usual amount."

Going to another extreme, we find Edison grappling with one of the biggest problems known to the authorities of New York—the disposal of its heavy snows. It is needless to say that witnessing the ordinary slow and costly procedure would put Edison on his mettle. "One time when they had a snow blockade in New York I started to build a machine with Batchelor—a big truck with a steam-engine and compressor on it. We would run along the street, gather all the snow up in front of us, pass it into the compressor, and deliver little blocks of ice behind us in the gutter, taking one-tenth the room of the snow, and not inconveniencing anybody. We could thus take care of a snow-storm by diminishing the bulk of material to be handled. The preliminary experiment we made was dropped because we went into other things. The machine would go as fast as a horse could walk."

Edison has always taken a keen interest in aerial flight, and has also experimented with aeroplanes, his preference inclining to the helicopter type, as noted in the newspapers and periodicals from time to time. The following statement from him refers to a type of aeroplane of great novelty and ingenuity: "James Gordon Bennett came to me and asked that I try some primary experiments to see if aerial navigation was feasible with 'heavier-than-air' machines. I got up a motor and put it on the scales and tried a large number of different things and contrivances connected to the motor, to see how it would lighten itself on the scales. I got some data and made up my mind that what was needed was a very powerful engine for its weight, in small compass. So I conceived of an engine employing guncotton. I took a lot of ticker paper tape, turned it into guncotton and got up an engine with an arrangement whereby I could feed this gun-cotton strip into the cylinder and explode it inside electrically. The feed took place between two copper rolls. The copper kept the temperature down, so that it could only explode up to the point where it was in contact with the feed rolls. It worked pretty well; but once the feed roll didn't save it, and the flame went through and exploded the whole roll and kicked up such a bad explosion I abandoned it. But the idea might be made to work."

Turning from the air to the earth, it is interesting to note that the introduction of the underground Edison system in New York made an appeal to inventive ingenuity and that one of the difficulties was met as follows: "When we first put the Pearl Street station in operation, in New York, we had cast-iron junction-boxes at the intersections of all the streets. One night, or about two o'clock in the morning, a policeman came in and said that something had exploded at the corner of William and Nassau streets. I happened to be in the station, and went out to see what it was. I found that the cover of the manhole, weighing about 200 pounds, had entirely disappeared, but everything inside was intact. It had even stripped some of the threads of the bolts, and we could never find that cover. I concluded it was either leakage of gas into the manhole, or else the acid used in pickling the casting had given off hydrogen, and air had leaked in, making an explosive mixture. As this was a pretty serious problem, and as we had a good many of the manholes, it worried me very much for fear that it would be repeated and the company might have to pay a lot of damages, especially in districts like that around William and Nassau, where there are a good many people about. If an explosion took place in the daytime it might lift a few of them up. However, I got around the difficulty by putting a little bottle of chloroform in each box, corked up, with a slight hole in the cork. The chloroform being volatile and very heavy, settled in the box and displaced all the air. I have never heard of an explosion in a manhole where this chloroform had been used. Carbon tetrachloride, now made electrically at Niagara Falls, is very cheap and would be ideal for the purpose."

Edison has never paid much attention to warfare, and has in general disdained to develop inventions for the destruction of life and property. Some years ago, however, he became the joint inventor of the Edison-Sims torpedo, with Mr. W. Scott Sims, who sought his co-operation. This is a dirigible submarine torpedo operated by electricity. In the torpedo proper, which is suspended from a long float so as to be submerged a few feet under water, are placed the small electric motor for propulsion and steering, and the explosive charge. The torpedo is controlled from the shore or ship through an electric cable which it pays out as it goes along, and all operations of varying the speed, reversing, and steering are performed at the will of the distant operator by means of currents sent through the cable. During the Spanish-American War of 1898 Edison suggested to the Navy Department the adoption of a compound of calcium carbide and calcium phosphite, which when placed in a shell and fired from a gun would explode as soon as it struck water and ignite, producing a blaze that would continue several minutes and make the ships of the enemy visible for four or five miles at sea. Moreover, the blaze could not be extinguished.

Edison has always been deeply interested in "conservation," and much of his work has been directed toward the economy of fuel in obtaining electrical energy directly from the consumption of coal. Indeed, it will be noted that the example of his handwriting shown in these volumes deals with the importance of obtaining available energy direct from the combustible without the enormous loss in the intervening stages that makes our best modern methods of steam generation and utilization so barbarously extravagant and wasteful. Several years ago, experimenting in this field, Edison devised and operated some ingenious pyromagnetic motors and generators, based, as the name implies, on the direct application of heat to the machines. The motor is founded upon the principle discovered by the famous Dr. William Gilbert—court physician to Queen Elizabeth, and the Father of modern electricity—that the magnetic properties of iron diminish with heat. At a light-red heat, iron becomes non-magnetic, so that a strong magnet exerts no influence over it. Edison employed this peculiar property by constructing a small machine in which a pivoted bar is alternately heated and cooled. It is thus attracted toward an adjacent electromagnet when cold and is uninfluenced when hot, and as the result motion is produced.

The pyromagnetic generator is based on the same phenomenon; its aim being of course to generate electrical energy directly from the heat of the combustible. The armature, or moving part of the machine, consists in reality of eight separate armatures all constructed of corrugated sheet iron covered with asbestos and wound with wire. These armatures are held in place by two circular iron plates, through the centre of which runs a shaft, carrying at its lower extremity a semicircular shield of fire-clay, which covers the ends of four of the armatures. The heat, of whatever origin, is applied from below, and the shaft being revolved, four of the armatures lose their magnetism constantly, while the other four gain it, so to speak. As the moving part revolves, therefore, currents of electricity are set up in the wires of the armatures and are collected by a commutator, as in an ordinary dynamo, placed on the upper end of the central shaft.

A great variety of electrical instruments are included in Edison's inventions, many of these in fundamental or earlier forms being devised for his systems of light and power, as noted already. There are numerous others, and it might be said with truth that Edison is hardly ever without some new device of this kind in hand, as he is by no means satisfied with the present status of electrical measurements. He holds in general that the meters of to-day, whether for heavy or for feeble currents, are too expensive, and that cheaper instruments are a necessity of the times. These remarks apply more particularly to what may be termed, in general, circuit meters. In other classes Edison has devised an excellent form of magnetic bridge, being an ingenious application of the principles of the familiar Wheatstone bridge, used so extensively for measuring the electrical resistance of wires; the testing of iron for magnetic qualities being determined by it in the same way. Another special instrument is a "dead beat" galvanometer which differs from the ordinary form of galvanometer in having no coils or magnetic needle. It depends for its action upon the heating effect of the current, which causes a fine platinum-iridium wire enclosed in a glass tube to expand; thus allowing a coiled spring to act on a pivoted shaft carrying a tiny mirror. The mirror as it moves throws a beam of light upon a scale and the indications are read by the spot of light. Most novel of all the apparatus of this measuring kind is the odoroscope, which is like the tasimeter described in an earlier chapter, except that a strip of gelatine takes the place of hard rubber, as the sensitive member. Besides being affected by heat, this device is exceedingly sensitive to moisture. A few drops of water or perfume thrown on the floor of a room are sufficient to give a very decided indication on the galvanometer in circuit with the instrument. Barometers, hygrometers, and similar instruments of great delicacy can be constructed on the principle of the odoroscope; and it may also be used in determining the character or pressure of gases and vapors in which it has been placed.

In the list of Edison's patents at the end of this work may be noted many other of his miscellaneous inventions, covering items such as preserving fruit in vacuo, making plate-glass, drawing wire, and metallurgical processes for treatment of nickel, gold, and copper ores; but to mention these inventions separately would trespass too much on our limited space here. Hence, we shall leave the interested reader to examine that list for himself.

From first to last Edison has filed in the United States Patent Office—in addition to more than 1400 applications for patents—some 120 caveats embracing not less than 1500 inventions. A "caveat" is essentially a notice filed by an inventor, entitling him to receive warning from the Office of any application for a patent for an invention that would "interfere" with his own, during the year, while he is supposed to be perfecting his device. The old caveat system has now been abolished, but it served to elicit from Edison a most astounding record of ideas and possible inventions upon which he was working, and many of which he of course reduced to practice. As an example of Edison's fertility and the endless variety of subjects engaging his thoughts, the following list of matters covered by ONE caveat is given. It is needless to say that all the caveats are not quite so full of "plums," but this is certainly a wonder.

Forty-one distinct inventions relating to the phonograph, covering various forms of recorders, arrangement of parts, making of records, shaving tool, adjustments, etc.

Eight forms of electric lamps using infusible earthy oxides and brought to high incandescence in vacuo by high potential current of several thousand volts; same character as impingement of X-rays on object in bulb.

A loud-speaking telephone with quartz cylinder and beam of ultra-violet light.

Four forms of arc light with special carbons.

A thermostatic motor.

A device for sealing together the inside part and bulb of an incandescent lamp mechanically.

Regulators for dynamos and motors.

Three devices for utilizing vibrations beyond the ultra violet.

A great variety of methods for coating incandescent lamp filaments with silicon, titanium, chromium, osmium, boron, etc.

Several methods of making porous filaments.

Several methods of making squirted filaments of a variety of materials, of which about thirty are specified.

Seventeen different methods and devices for separating magnetic ores.

A continuously operative primary battery.

A musical instrument operating one of Helmholtz's artificial larynxes.

A siren worked by explosion of small quantities of oxygen and hydrogen mixed.

Three other sirens made to give vocal sounds or articulate speech.

A device for projecting sound-waves to a distance without spreading and in a straight line, on the principle of smoke rings.

A device for continuously indicating on a galvanometer the depths of the ocean.

A method of preventing in a great measure friction of water against the hull of a ship and incidentally preventing fouling by barnacles.

A telephone receiver whereby the vibrations of the diaphragm are considerably amplified.

Two methods of "space" telegraphy at sea.

An improved and extended string telephone.

Devices and method of talking through water for considerable distances.

An audiphone for deaf people.

Sound-bridge for measuring resistance of tubes and other materials for conveying sound.

A method of testing a magnet to ascertain the existence of flaws in the iron or steel composing the same.

Method of distilling liquids by incandescent conductor immersed in the liquid.

Method of obtaining electricity direct from coal.

An engine operated by steam produced by the hydration and dehydration of metallic salts.

Device and method for telegraphing photographically.

Carbon crucible kept brilliantly incandescent by current in vacuo, for obtaining reaction with refractory metals.

Device for examining combinations of odors and their changes by rotation at different speeds.

From one of the preceding items it will be noted that even in the eighties Edison perceived much advantage to be gained in the line of economy by the use of lamp filaments employing refractory metals in their construction. From another caveat, filed in 1889, we extract the following, which shows that he realized the value of tungsten also for this purpose. "Filaments of carbon placed in a combustion tube with a little chloride ammonium. Chloride tungsten or titanium passed through hot tube, depositing a film of metal on the carbon; or filaments of zirconia oxide, or alumina or magnesia, thoria or other infusible oxides mixed or separate, and obtained by moistening and squirting through a die, are thus coated with above metals and used for incandescent lamps. Osmium from a volatile compound of same thus deposited makes a filament as good as carbon when in vacuo."

In 1888, long before there arose the actual necessity of duplicating phonograph records so as to produce replicas in great numbers, Edison described in one of his caveats a method and process much similar to the one which was put into practice by him in later years. In the same caveat he describes an invention whereby the power to indent on a phonograph cylinder, instead of coming directly from the voice, is caused by power derived from the rotation or movement of the phonogram surface itself. He did not, however, follow up this invention and put it into practice. Some twenty years later it was independently invented and patented by another inventor. A further instance of this kind is a method of telegraphy at sea by means of a diaphragm in a closed port-hole flush with the side of the vessel, and actuated by a steam-whistle which is controlled by a lever, similarly to a Morse key. A receiving diaphragm is placed in another and near-by chamber, which is provided with very sensitive stethoscopic ear-pieces, by which the Morse characters sent from another vessel may be received. This was also invented later by another inventor, and is in use to-day, but will naturally be rivalled by wireless telegraphy. Still another instance is seen in one of Edison's caveats, where he describes a method of distilling liquids by means of internally applied heat through electric conductors. Although Edison did not follow up the idea and take out a patent, this system of distillation was later hit upon by others and is in use at the present time.

In the foregoing pages of this chapter the authors have endeavored to present very briefly a sketchy notion of the astounding range of Edison's practical ideas, but they feel a sense of impotence in being unable to deal adequately with the subject in the space that can be devoted to it. To those who, like the authors, have had the privilege of examining the voluminous records which show the flights of his imagination, there comes a feeling of utter inadequacy to convey to others the full extent of the story they reveal.

The few specific instances above related, although not representing a tithe of Edison's work, will probably be sufficient to enable the reader to appreciate to some extent his great wealth of ideas and fertility of imagination, and also to realize that this imagination is not only intensely practical, but that it works prophetically along lines of natural progress.



CHAPTER XXIV

EDISON'S METHOD IN INVENTING

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, combined 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."

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. Taking one of the laboratory note-books, he will write in it a memorandum of the experiments to be tried, illustrated, if necessary, by sketches. This book is then passed on to that member of the experimental staff whose special training and experience are best adapted to the work. Here strenuousness is expected; and an immediate commencement of investigation and prompt report are required. Sometimes the subject may be such as to call for a long line of frequent tests which necessitate patient and accurate attention to minute details. Results must be reported often—daily, or possibly with still greater frequency. Edison does not forget what is going on; but in his daily tours through the laboratory keeps in touch with all the work that is under the hands of his various assistants, showing by an instant grasp of the present conditions of any experiment that he has a full consciousness of its meaning and its reference to his original conception.

The year 1869 saw the beginning of Edison's career as an acknowledged inventor of commercial devices. From the outset, an innate recognition of system dictated the desirability and wisdom of preserving records of his experiments and inventions. The primitive records, covering the earliest years, were mainly jotted down on loose sheets of paper covered with sketches, notes, and data, pasted into large scrap-books, or preserved in packages; but with the passing of years and enlargement of his interests, it became the practice to make all original laboratory notes in large, uniform books. This course was pursued until the Menlo Park period, when he instituted a new regime that has been continued down to the present day. A standard form of note-book, about eight and a half by six inches, containing about two hundred pages, was adopted. A number of these books were (and are now) always to be found scattered around in the different sections of the laboratory, and in them have been noted by Edison all his ideas, sketches, and memoranda. Details of the various experiments concerning them have been set down by his assistants from time to time.

These later laboratory note-books, of which there are now over one thousand in the series, are eloquent in the history they reveal of the strenuous labors of Edison and his assistants and the vast fields of research he has covered during the last thirty years. They are overwhelmingly rich in biographic material, but analysis would be a prohibitive task for one person, and perhaps interesting only to technical readers. Their pages cover practically every department of science. The countless thousands of separate experiments recorded exhibit 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. For instance, when Edison was investigating a certain problem of importance many years ago, the note-books show that on this point alone about fifteen thousand experiments and tests were made by one of his assistants.

A most casual glance over these note-books will illustrate the following remark, which was made to one of the writers not long ago by a member of the laboratory staff who has been experimenting there for twenty years: "Edison can think of more ways of doing a thing than any man I ever saw or heard of. He tries everything and never lets up, even though failure is apparently staring him in the face. He only stops when he simply can't go any further on that particular line. When he decides on any mode of procedure he gives his notes to the experimenter and lets him alone, only stepping in from time to time to look at the operations and receive reports of progress."

The history of the development of the telephone transmitter, phonograph, incandescent lamp, dynamo, electrical distributing systems from central stations, electric railway, ore-milling, cement, motion pictures, and a host of minor inventions may be found embedded in the laboratory note-books. A passing glance at a few pages of these written records will serve to illustrate, though only to a limited extent, the thoroughness of Edison's method. It is to be observed that these references can be but of the most meagre kind, and must be regarded as merely throwing a side-light on the subject itself. For instance, the complex problem of a practical telephone transmitter gave rise to a series of most exhaustive experiments. Combinations in almost infinite variety, including gums, chemical compounds, oils, minerals, and metals were suggested by Edison; and his assistants were given long lists of materials to try with reference to predetermined standards of articulation, degrees of loudness, and perfection of hissing sounds. The note-books contain hundreds of pages showing that a great many thousands of experiments were tried and passed upon. Such remarks as "N. G."; "Pretty good"; "Whistling good, but no articulation"; "Rattly"; "Articulation, whispering, and whistling good"; "Best to-night so far"; and others are noted opposite the various combinations as they were tried. Thus, one may follow the investigation through a maze of experiments which led up to the successful invention of the carbon button transmitter, the vital device to give the telephone its needed articulation and perfection.

The two hundred and odd note-books, covering the strenuous period during which Edison was carrying on his electric-light experiments, tell on their forty thousand pages or more a fascinating story of the evolution of a new art in its entirety. From the crude beginnings, through all the varied phases of this evolution, the operations of a master mind are apparent from the contents of these pages, in which are recorded the innumerable experiments, calculations, and tests that ultimately brought light out of darkness.

The early work on a metallic conductor for lamps gave rise to some very thorough research on melting and alloying metals, the preparation of metallic oxides, the coating of fine wires by immersing them in a great variety of chemical solutions. Following his usual custom, Edison would indicate the lines of experiment to be followed, which were carried out and recorded in the note-books. He himself, in January, 1879, made personally a most minute and searching investigation into the properties and behavior of plating-iridium, boron, rutile, zircon, chromium, molybdenum, and nickel, under varying degrees of current strength, on which there may be found in the notes about forty pages of detailed experiments and deductions in his own handwriting, concluding with the remark (about nickel): "This is a great discovery for electric light in the way of economy."

This period of research on nickel, etc., was evidently a trying one, for after nearly a month's close application he writes, on January 27, 1879: "Owing to the enormous power of the light my eyes commenced to pain after seven hours' work, and I had to quit." On the next day appears the following entry: "Suffered the pains of hell with my eyes last night from 10 P.M. till 4 A.M., when got to sleep with a big dose of morphine. Eyes getting better, and do not pain much at 4 P.M.; but I lose to-day."

The "try everything" spirit of Edison's method is well illustrated in this early period by a series of about sixteen hundred resistance tests of various ores, minerals, earths, etc., occupying over fifty pages of one of the note-books relating to the metallic filament for his lamps.

But, as the reader has already learned, the metallic filament was soon laid aside in favor of carbon, and we find in the laboratory notes an amazing record of research and experiment conducted in the minute and searching manner peculiar to Edison's method. His inquiries were directed along all the various roads leading to the desired goal, for long before he had completed the invention of a practical lamp he realized broadly the fundamental requirements of a successful system of electrical distribution, and had given instructions for the making of a great variety of calculations which, although far in advance of the time, were clearly foreseen by him to be vitally important in the ultimate solution of the complicated problem. Thus we find many hundreds of pages of the note-books covered with computations and calculations by Mr. Upton, not only on the numerous ramifications of the projected system and comparisons with gas, but also on proposed forms of dynamos and the proposed station in New York. A mere recital by titles of the vast number of experiments and tests on carbons, lamps, dynamos, armatures, commutators, windings, systems, regulators, sockets, vacuum-pumps, and the thousand and one details relating to the subject in general, originated by Edison, and methodically and systematically carried on under his general direction, would fill a great many pages here, and even then would serve only to convey a confused impression of ceaseless probing.

It is possible only to a broad, comprehensive mind well stored with knowledge, and backed with resistless, boundless energy, that such a diversified series of experiments and investigations could be carried on simultaneously and assimilated, even though they should relate to a class of phenomena already understood and well defined. But if we pause to consider that the commercial subdivision of the electric current (which was virtually an invention made to order) involved the solution of problems so unprecedented that even they themselves had to be created, we cannot but conclude that the afflatus of innate genius played an important part in the unique methods of investigation instituted by Edison at that and other times.

The idea of attributing great successes to "genius" has always been repudiated by Edison, as evidenced by his historic remark that "Genius is 1 per cent. inspiration and 99 per cent. perspiration." Again, in a conversation many years ago at the laboratory between Edison, Batchelor, and E. H. Johnson, the latter made allusion to Edison's genius as evidenced by some of his achievements, when Edison replied:

"Stuff! I tell you genius is hard work, stick-to-it-iveness, and common sense."

"Yes," said Johnson, "I admit there is all that to it, but there's still more. Batch and I have those qualifications, but although we knew quite a lot about telephones, and worked hard, we couldn't invent a brand-new non-infringing telephone receiver as you did when Gouraud cabled for one. Then, how about the subdivision of the electric light?"

"Electric current," corrected Edison.

"True," continued Johnson; "you were the one to make that very distinction. The scientific world had been working hard on subdivision for years, using what appeared to be common sense. Results worse than nil. Then you come along, and about the first thing you do, after looking the ground over, is to start off in the opposite direction, which subsequently proves to be the only possible way to reach the goal. It seems to me that this is pretty close to the dictionary definition of genius."

It is said that Edison replied rather incoherently and changed the topic of conversation.

This innate modesty, however, does not prevent Edison from recognizing and classifying his own methods of investigation. In a conversation with two old associates recently (April, 1909), he remarked: "It has been said of me that my methods are empirical. That is true only so far as chemistry is concerned. Did you ever realize that practically all industrial chemistry is colloidal in its nature? Hard rubber, celluloid, glass, soap, paper, and lots of others, all have to deal with amorphous substances, as to which comparatively little has been really settled. My methods are similar to those followed by Luther Burbank. He plants an acre, and when this is in bloom he inspects it. He has a sharp eye, and can pick out of thousands a single plant that has promise of what he wants. From this he gets the seed, and uses his skill and knowledge in producing from it a number of new plants which, on development, furnish the means of propagating an improved variety in large quantity. So, when I am after a chemical result that I have in mind, I may make hundreds or thousands of experiments out of which there may be one that promises results in the right direction. This I follow up to its legitimate conclusion, discarding the others, and usually get what I am after. There is no doubt about this being empirical; but when it comes to problems of a mechanical nature, I want to tell you that all I've ever tackled and solved have been done by hard, logical thinking." The intense earnestness and emphasis with which this was said were very impressive to the auditors. This empirical method may perhaps be better illustrated by a specific example. During the latter part of the storage battery investigations, after the form of positive element had been determined upon, it became necessary to ascertain what definite proportions and what quality of nickel hydrate and nickel flake would give the best results. A series of positive tubes were filled with the two materials in different proportions—say, nine parts hydrate to one of flake; eight parts hydrate to two of flake; seven parts hydrate to three of flake, and so on through varying proportions. Three sets of each of these positives were made, and all put into separate test tubes with a uniform type of negative element. These were carried through a long series of charges and discharges under strict test conditions. From the tabulated results of hundreds of tests there were selected three that showed the best results. These, however, showed only the superiority of certain PROPORTIONS of the materials. The next step would be to find out the best QUALITY. Now, as there are several hundred variations in the quality of nickel flake, and perhaps a thousand ways to make the hydrate, it will be realized that Edison's methods led to stupendous detail, for these tests embraced a trial of all the qualities of both materials in the three proportions found to be most suitable. Among these many thousands of experiments any that showed extraordinary results were again elaborated by still further series of tests, until Edison was satisfied that he had obtained the best result in that particular line.

The laboratory note-books do not always tell the whole story or meaning of an experiment that may be briefly outlined on one of their pages. For example, the early filament made of a mixture of lampblack and tar is merely a suggestion in the notes, but its making afforded an example of Edison's pertinacity. These materials, when mixed, became a friable mass, which he had found could be brought into such a cohesive, putty-like state by manipulation, as to be capable of being rolled out into filaments as fine as seven-thousandths of an inch in cross-section. One of the laboratory assistants was told to make some of this mixture, knead it, and roll some filaments. After a time he brought the mass to Edison, and said:

"There's something wrong about this, for it crumbles even after manipulating it with my fingers."

"How long did you knead it?" said Edison.

"Oh! more than an hour," replied the assistant.

"Well, just keep on for a few hours more and it will come out all right," was the rejoinder. And this proved to be correct, for, after a prolonged kneading and rolling, the mass changed into a cohesive, stringy, homogeneous putty. It was from a mixture of this kind that spiral filaments were made and used in some of the earliest forms of successful incandescent lamps; indeed, they are described and illustrated in Edison's fundamental lamp patent (No. 223,898).

The present narrative would assume the proportions of a history of the incandescent lamp, should the authors attempt to follow Edison's investigations through the thousands of pages of note-books away back in the eighties and early nineties. Improvement of the lamp was constantly in his mind all those years, and besides the vast amount of detail experimental work he laid out for his assistants, he carried on a great deal of research personally. Sometimes whole books are filled in his own handwriting with records of experiments showing every conceivable variation of some particular line of inquiry; each trial bearing some terse comment expressive of results. In one book appear the details of one of these experiments on September 3, 1891, at 4.30 A.M., with the comment: "Brought up lamp higher than a 16-c.p. 240 was ever brought before—Hurrah!" Notwithstanding the late hour, he turns over to the next page and goes on to write his deductions from this result as compared with those previously obtained. Proceeding day by day, as appears by this same book, he follows up another line of investigation on lamps, apparently full of difficulty, for after one hundred and thirty-two other recorded experiments we find this note: "Saturday 3.30 went home disgusted with incandescent lamps." This feeling was evidently evanescent, for on the succeeding Monday the work was continued and carried on by him as keenly as before, as shown by the next batch of notes.

This is the only instance showing any indication of impatience that the authors have found in looking through the enormous mass of laboratory notes. All his assistants agree that Edison is the most patient, tireless experimenter that could be conceived of. Failures do not distress him; indeed, he regards them as always useful, as may be gathered from the following, related by Dr. E. G. Acheson, formerly one of his staff: "I once made an experiment in Edison's laboratory at Menlo Park during the latter part of 1880, and the results were not as looked for. I considered the experiment a perfect failure, and while bemoaning the results of this apparent failure Mr. Edison entered, and, after learning the facts of the case, cheerfully remarked that I should not look upon it as a failure, for he considered every experiment a success, as in all cases it cleared up the atmosphere, and even though it failed to accomplish the results sought for, it should prove a valuable lesson for guidance in future work. I believe that Mr. Edison's success as an experimenter was, to a large extent, due to this happy view of all experiments."

Edison has frequently remarked that out of a hundred experiments he does not expect more than one to be successful, and as to that one he is always suspicious until frequent repetition has verified the original results.

This patient, optimistic view of the outcome of experiments has remained part of his character down to this day, just as his painstaking, minute, incisive methods are still unchanged. But to the careless, stupid, or lazy person he is a terror for the short time they remain around him. Honest mistakes may be tolerated, but not carelessness, incompetence, or lack of attention to business. In such cases Edison is apt to express himself freely and forcibly, as when he was asked why he had parted with a certain man, he said: "Oh, he was so slow that it would take him half an hour to get out of the field of a microscope." Another instance will be illustrative. Soon after the Brockton (Massachusetts) central station was started in operation many years ago, he wrote a note to Mr. W. S. Andrews, containing suggestions as to future stations, part of which related to the various employees and their duties. After outlining the duties of the meter man, Edison says: "I should not take too young a man for this, say, a man from twenty-three to thirty years old, bright and businesslike. Don't want any one who yearns to enter a laboratory and experiment. We have a bad case of that at Brockton; he neglects business to potter. What we want is a good lamp average and no unprofitable customer. You should have these men on probation and subject to passing an examination by me. This will wake them up."

Edison's examinations are no joke, according to Mr. J. H. Vail, formerly one of the Menlo Park staff. "I wanted a job," he said, "and was ambitious to take charge of the dynamo-room. Mr. Edison led me to a heap of junk in a corner and said: 'Put that together and let me know when it's running.' I didn't know what it was, but received a liberal education in finding out. It proved to be a dynamo, which I finally succeeded in assembling and running. I got the job." Another man who succeeded in winning a place as assistant was Mr. John F. Ott, who has remained in his employ for over forty years. In 1869, when Edison was occupying his first manufacturing shop (the third floor of a small building in Newark), he wanted a first-class mechanician, and Mr. Ott was sent to him. "He was then an ordinary-looking young fellow," says Mr. Ott, "dirty as any of the other workmen, unkempt, and not much better dressed than a tramp, but I immediately felt that there was a great deal in him." This is the conversation that ensued, led by Mr. Edison's question:

"What do you want?"

"Work."

"Can you make this machine work?" (exhibiting it and explaining its details).

"Yes."

"Are you sure?"

"Well, you needn't pay me if I don't."

And thus Mr. Ott went to work and succeeded in accomplishing the results desired. Two weeks afterward Mr. Edison put him in charge of the shop.

Edison's life fairly teems with instances of unruffled patience in the pursuit of experiments. When he feels thoroughly impressed with the possibility of accomplishing a certain thing, he will settle down composedly to investigate it to the end.

This is well illustrated in a story relating to his invention of the type of storage battery bearing his name. Mr. W. S. Mallory, one of his closest associates for many years, is the authority for the following: "When Mr. Edison decided to shut down the ore-milling plant at Edison, New Jersey, in which I had been associated with him, it became a problem as to what he could profitably take up next, and we had several discussions about it. He finally thought that a good storage battery was a great requisite, and decided to try and devise a new type, for he declared emphatically he would make no battery requiring sulphuric acid. After a little thought he conceived the nickel-iron idea, and started to work at once with characteristic energy. About 7 or 7.30 A.M. he would go down to the laboratory and experiment, only stopping for a short time at noon to eat a lunch sent down from the house. About 6 o'clock the carriage would call to take him to dinner, from which he would return by 7.30 or 8 o'clock to resume work. The carriage came again at midnight to take him home, but frequently had to wait until 2 or 3 o'clock, and sometimes return without him, as he had decided to continue all night.

"This had been going on more than five months, seven days a week, when I was called down to the laboratory to see him. I found him at a bench about three feet wide and twelve to fifteen feet long, on which there were hundreds of little test cells that had been made up by his corps of chemists and experimenters. He was seated at this bench testing, figuring, and planning. I then learned that he had thus made over nine thousand experiments in trying to devise this new type of storage battery, but had not produced a single thing that promised to solve the question. In view of this immense amount of thought and labor, my sympathy got the better of my judgment, and I said: 'Isn't it a shame that with the tremendous amount of work you have done you haven't been able to get any results?' Edison turned on me like a flash, and with a smile replied: 'Results! Why, man, I have gotten a lot of results! I know several thousand things that won't work.'

"At that time he sent me out West on a special mission. On my return, a few weeks later, his experiments had run up to over ten thousand, but he had discovered the missing link in the combination sought for. Of course, we all remember how the battery was completed and put on the market. Then, because he was dissatisfied with it, he stopped the sales and commenced a new line of investigation, which has recently culminated successfully. I shouldn't wonder if his experiments on the battery ran up pretty near to fifty thousand, for they fill more than one hundred and fifty of the note-books, to say nothing of some thousands of tests in curve sheets."

Although Edison has an absolute disregard for the total outlay of money in investigation, he is particular to keep down the cost of individual experiments to a minimum, for, as he observed to one of his assistants: "A good many inventors try to develop things life-size, and thus spend all their money, instead of first experimenting more freely on a small scale." To Edison life is not only a grand opportunity to find out things by experiment, but, when found, to improve them by further experiment. One night, after receiving a satisfactory report of progress from Mr. Mason, superintendent of the cement plant, he said: "The only way to keep ahead of the procession is to experiment. If you don't, the other fellow will. When there's no experimenting there's no progress. Stop experimenting and you go backward. If anything goes wrong, experiment until you get to the very bottom of the trouble."

It is easy to realize, therefore, that a character so thoroughly permeated with these ideas is not apt to stop and figure out expense when in hot pursuit of some desired object. When that object has been attained, however, and it passes from the experimental to the commercial stage, Edison's monetary views again come into strong play, but they take a diametrically opposite position, for he then begins immediately to plan the extreme of economy in the production of the article. A thousand and one instances could be quoted in illustration; but as they would tend to change the form of this narrative into a history of economy in manufacture, it will suffice to mention but one, and that a recent occurrence, which serves to illustrate how closely he keeps in touch with everything, and also how the inventive faculty and instinct of commercial economy run close together. It was during Edison's winter stay in Florida, in March, 1909. He had reports sent to him daily from various places, and studied them carefully, for he would write frequently with comments, instructions, and suggestions; and in one case, commenting on the oiling system at the cement plant, he wrote: "Your oil losses are now getting lower, I see." Then, after suggesting some changes to reduce them still further, he went on to say: "Here is a chance to save a mill per barrel based on your regular daily output."

This thorough consideration of the smallest detail is essentially characteristic of Edison, not only in economy of manufacture, but in all his work, no matter of what kind, whether it be experimenting, investigating, testing, or engineering. To follow him through the labyrinthine paths of investigation contained in the great array of laboratory note-books is to become involved in a mass of minutely detailed searches which seek to penetrate the inmost recesses of nature by an ultimate analysis of an infinite variety of parts. As the reader will obtain a fuller comprehension of this idea, and of Edison's methods, by concrete illustration rather than by generalization, the authors have thought it well to select at random two typical instances of specific investigations out of the thousands that are scattered through the notebooks. These will be found in the following extracts from one of the note-books, and consist of Edison's instructions to be carried out in detail by his experimenters:

"Take, say, 25 lbs. hard Cuban asphalt and separate all the different hydrocarbons, etc., as far as possible by means of solvents. It will be necessary first to dissolve everything out by, say, hot turpentine, then successively treat the residue with bisulphide carbon, benzol, ether, chloroform, naphtha, toluol, alcohol, and other probable solvents. After you can go no further, distil off all the solvents so the asphalt material has a tar-like consistency. Be sure all the ash is out of the turpentine portion; now, after distilling the turpentine off, act on the residue with all the solvents that were used on the residue, using for the first the solvent which is least likely to dissolve a great part of it. By thus manipulating the various solvents you will be enabled probably to separate the crude asphalt into several distinct hydrocarbons. Put each in a bottle after it has been dried, and label the bottle with the process, etc., so we may be able to duplicate it; also give bottle a number and describe everything fully in note-book."

"Destructively distil the following substances down to a point just short of carbonization, so that the residuum can be taken out of the retort, powdered, and acted on by all the solvents just as the asphalt in previous page. The distillation should be carried to, say, 600 degrees or 700 degrees Fahr., but not continued long enough to wholly reduce mass to charcoal, but always run to blackness. Separate the residuum in as many definite parts as possible, bottle and label, and keep accurate records as to process, weights, etc., so a reproduction of the experiment can at any time be made: Gelatine, 4 lbs.; asphalt, hard Cuban, 10 lbs.; coal-tar or pitch, 10 lbs.; wood-pitch, 10 lbs.; Syrian asphalt, 10 lbs.; bituminous coal, 10 lbs.; cane-sugar, 10 lbs.; glucose, 10 lbs.; dextrine, 10 lbs.; glycerine, 10 lbs.; tartaric acid, 5 lbs.; gum guiac, 5 lbs.; gum amber, 3 lbs.; gum tragacanth, 3 Lbs.; aniline red, 1 lb.; aniline oil, 1 lb.; crude anthracene, 5 lbs.; petroleum pitch, 10 lbs.; albumen from eggs, 2 lbs.; tar from passing chlorine through aniline oil, 2 lbs.; citric acid, 5 lbs.; sawdust of boxwood, 3 lbs.; starch, 5 lbs.; shellac, 3 lbs.; gum Arabic, 5 lbs.; castor oil, 5 lbs."

The empirical nature of his method will be apparent from an examination of the above items; but in pursuing it he leaves all uncertainty behind and, trusting nothing to theory, he acquires absolute knowledge. Whatever may be the mental processes by which he arrives at the starting-point of any specific line of research, the final results almost invariably prove that he does not plunge in at random; indeed, as an old associate remarked: "When Edison takes up any proposition in natural science, his perceptions seem to be elementally broad and analytical, that is to say, in addition to the knowledge he has acquired from books and observation, he appears to have an intuitive apprehension of the general order of things, as they might be supposed to exist in natural relation to each other. It has always seemed to me that he goes to the core of things at once."

Although nothing less than results from actual experiments are acceptable to him as established facts, this view of Edison may also account for his peculiar and somewhat weird ability to "guess" correctly, a faculty which has frequently enabled him to take short cuts to lines of investigation whose outcome has verified in a most remarkable degree statements apparently made offhand and without calculation. Mr. Upton says: "One of the main impressions left upon me, after knowing Mr. Edison for many years, is the marvellous accuracy of his guesses. He will see the general nature of a result long before it can be reached by mathematical calculation." This was supplemented by one of his engineering staff, who remarked: "Mr. Edison can guess better than a good many men can figure, and so far as my experience goes, I have found that he is almost invariably correct. His guess is more than a mere starting-point, and often turns out to be the final solution of a problem. I can only account for it by his remarkable insight and wonderful natural sense of the proportion of things, in addition to which he seems to carry in his head determining factors of all kinds, and has the ability to apply them instantly in considering any mechanical problem."

While this mysterious intuitive power has been of the greatest advantage in connection with the vast number of technical problems that have entered into his life-work, there have been many remarkable instances in which it has seemed little less than prophecy, and it is deemed worth while to digress to the extent of relating two of them. One day in the summer of 1881, when the incandescent lamp-industry was still in swaddling clothes, Edison was seated in the room of Major Eaton, vice-president of the Edison Electric Light Company, talking over business matters, when Mr. Upton came in from the lamp factory at Menlo Park, and said: "Well, Mr. Edison, we completed a thousand lamps to-day." Edison looked up and said "Good," then relapsed into a thoughtful mood. In about two minutes he raised his head, and said: "Upton, in fifteen years you will be making forty thousand lamps a day." None of those present ventured to make any remark on this assertion, although all felt that it was merely a random guess, based on the sanguine dream of an inventor. The business had not then really made a start, and being entirely new was without precedent upon which to base any such statement, but, as a matter of fact, the records of the lamp factory show that in 1896 its daily output of lamps was actually about forty thousand.

The other instance referred to occurred shortly after the Edison Machine Works was moved up to Schenectady, in 1886. One day, when he was at the works, Edison sat down and wrote on a sheet of paper fifteen separate predictions of the growth and future of the electrical business. Notwithstanding the fact that the industry was then in an immature state, and that the great boom did not set in until a few years afterward, twelve of these predictions have been fully verified by the enormous growth and development in all branches of the art.

What the explanation of this gift, power, or intuition may be, is perhaps better left to the psychologist to speculate upon. If one were to ask Edison, he would probably say, "Hard work, not too much sleep, and free use of the imagination." Whether or not it would be possible for the average mortal to arrive at such perfection of "guessing" by faithfully following this formula, even reinforced by the Edison recipe for stimulating a slow imagination with pastry, is open for demonstration.

Somewhat allied to this curious faculty is another no less remarkable, and that is, the ability to point out instantly an error in a mass of reported experimental results. While many instances could be definitely named, a typical one, related by Mr. J. D. Flack, formerly master mechanic at the lamp factory, may be quoted: "During the many years of lamp experimentation, batches of lamps were sent to the photometer department for test, and Edison would examine the tabulated test sheets. He ran over every item of the tabulations rapidly, and, apparently without any calculation whatever, would check off errors as fast as he came to them, saying: 'You have made a mistake; try this one over.' In every case the second test proved that he was right. This wonderful aptitude for infallibly locating an error without an instant's hesitation for mental calculation, has always appealed to me very forcibly."

The ability to detect errors quickly in a series of experiments is one of the things that has enabled Edison to accomplish such a vast amount of work as the records show. Examples of the minuteness of detail into which his researches extend have already been mentioned, and as there are always a number of such investigations in progress at the laboratory, this ability stands Edison in good stead, for he is thus enabled to follow, and, if necessary, correct each one step by step. In this he is aided by the great powers of a mind that is able to free itself from absorbed concentration on the details of one problem, and instantly to shift over and become deeply and intelligently concentrated in another and entirely different one. For instance, he may have been busy for hours on chemical experiments, and be called upon suddenly to determine some mechanical questions. The complete and easy transition is the constant wonder of his associates, for there is no confusion of ideas resulting from these quick changes, no hesitation or apparent effort, but a plunge into the midst of the new subject, and an instant acquaintance with all its details, as if he had been studying it for hours.

A good stiff difficulty—one which may, perhaps, appear to be an unsurmountable obstacle—only serves to make Edison cheerful, and brings out variations of his methods in experimenting. Such an occurrence will start him thinking, which soon gives rise to a line of suggestions for approaching the trouble from various sides; or he will sit down and write out a series of eliminations, additions, or changes to be worked out and reported upon, with such variations as may suggest themselves during their progress. It is at such times as these that his unfailing patience and tremendous resourcefulness are in evidence. Ideas and expedients are poured forth in a torrent, and although some of them have temporarily appeared to the staff to be ridiculous or irrelevant, they have frequently turned out to be the ones leading to a correct solution of the trouble.

Edison's inexhaustible resourcefulness and fertility of ideas have contributed largely to his great success, and have ever been a cause of amazement to those around him. Frequently, when it would seem to others that the extreme end of an apparently blind alley had been reached, and that it was impossible to proceed further, he has shown that there were several ways out of it. Examples without number could be quoted, but one must suffice by way of illustration. During the progress of the ore-milling work at Edison, it became desirable to carry on a certain operation by some special machinery. He requested the proper person on his engineering staff to think this matter up and submit a few sketches of what he would propose to do. He brought three drawings to Edison, who examined them and said none of them would answer. The engineer remarked that it was too bad, for there was no other way to do it. Mr. Edison turned to him quickly, and said: "Do you mean to say that these drawings represent the only way to do this work?" To which he received the reply: "I certainly do." Edison said nothing. This happened on a Saturday. He followed his usual custom of spending Sunday at home in Orange. When he returned to the works on Monday morning, he took with him sketches he had made, showing FORTY-EIGHT other ways of accomplishing the desired operation, and laid them on the engineer's desk without a word. Subsequently one of these ideas, with modifications suggested by some of the others, was put into successful practice.

Difficulties seem to have a peculiar charm for Edison, whether they relate to large or small things; and although the larger matters have contributed most to the history of the arts, the same carefulness of thought has often been the means of leading to improvements of permanent advantage even in minor details. For instance, in the very earliest days of electric lighting, the safe insulation of two bare wires fastened together was a serious problem that was solved by him. An iron pot over a fire, some insulating material melted therein, and narrow strips of linen drawn through it by means of a wooden clamp, furnished a readily applied and adhesive insulation, which was just as perfect for the purpose as the regular and now well-known insulating tape, of which it was the forerunner.

Dubious results are not tolerated for a moment in Edison's experimental work. Rather than pass upon an uncertainty, the experiment will be dissected and checked minutely in order to obtain absolute knowledge, pro and con. This searching method is followed not only in chemical or other investigations, into which complexities might naturally enter, but also in more mechanical questions, where simplicity of construction might naturally seem to preclude possibilities of uncertainty. For instance, at the time when he was making strenuous endeavors to obtain copper wire of high conductivity, strict laboratory tests were made of samples sent by manufacturers. One of these samples tested out poorer than a previous lot furnished from the same factory. A report of this to Edison brought the following note: "Perhaps the —— wire had a bad spot in it. Please cut it up into lengths and test each one and send results to me immediately." Possibly the electrical fraternity does not realize that this earnest work of Edison, twenty-eight years ago, resulted in the establishment of the high quality of copper wire that has been the recognized standard since that time. Says Edison on this point: "I furnished the expert and apparatus to the Ansonia Brass and Copper Company in 1883, and he is there yet. It was this expert and this company who pioneered high-conductivity copper for the electrical trade."

Nor is it generally appreciated in the industry that the adoption of what is now regarded as a most obvious proposition—the high-economy incandescent lamp—was the result of that characteristic foresight which there has been occasion to mention frequently in the course of this narrative, together with the courage and "horse-sense" which have always been displayed by the inventor in his persistent pushing out with far-reaching ideas, in the face of pessimistic opinions. As is well known, the lamps of the first ten or twelve years of incandescent lighting were of low economy, but had long life. Edison's study of the subject had led him to the conviction that the greatest growth of the electric-lighting industry would be favored by a lamp taking less current, but having shorter, though commercially economical life; and after gradually making improvements along this line he developed, finally, a type of high-economy lamp which would introduce a most radical change in existing conditions, and lead ultimately to highly advantageous results. His start on this lamp, and an expressed desire to have it manufactured for regular use, filled even some of his business associates with dismay, for they could see nothing but disaster ahead in forcing such a lamp on the market. His persistence and profound conviction of the ultimate results were so strong and his arguments so sound, however, that the campaign was entered upon. Although it took two or three years to convince the public of the correctness of his views, the idea gradually took strong root, and has now become an integral principle of the business.

In this connection it may be noted that with remarkable prescience Edison saw the coming of the modern lamps of to-day, which, by reason of their small consumption of energy to produce a given candle-power, have dismayed central-station managers. A few years ago a consumption of 3.1 watts per candle-power might safely be assumed as an excellent average, and many stations fixed their rates and business on such a basis. The results on income when the consumption, as in the new metallic-filament lamps, drops to 1.25 watts per candle can readily be imagined. Edison has insisted that central stations are selling light and not current; and he points to the predicament now confronting them as truth of his assertion that when selling light they share in all the benefits of improvement, but that when they sell current the consumer gets all those benefits without division. The dilemma is encountered by central stations in a bewildered way, as a novel and unexpected experience; but Edison foresaw the situation and warned against it long ago. It is one of the greatest gifts of statesmanship to see new social problems years before they arise and solve them in advance. It is one of the greatest attributes of invention to foresee and meet its own problems in exactly the same way.



CHAPTER XXV

THE LABORATORY AT ORANGE AND THE STAFF

A LIVING interrogation-point and a born investigator from childhood, Edison has never been without a laboratory of some kind for upward of half a century.

In youthful years, as already described in this book, he became ardently interested in chemistry, and even at the early age of twelve felt the necessity for a special nook of his own, where he could satisfy his unconvinced mind of the correctness or inaccuracy of statements and experiments contained in the few technical books then at his command.

Ordinarily he was like other normal lads of his age—full of boyish, hearty enjoyments—but withal possessed of an unquenchable spirit of inquiry and an insatiable desire for knowledge. Being blessed with a wise and discerning mother, his aspirations were encouraged; and he was allowed a corner in her cellar. It is fair to offer tribute here to her bravery as well as to her wisdom, for at times she was in mortal terror lest the precocious experimenter below should, in his inexperience, make some awful combination that would explode and bring down the house in ruins on himself and the rest of the family.

Fortunately no such catastrophe happened, but young Edison worked away in his embryonic laboratory, satisfying his soul and incidentally depleting his limited pocket-money to the vanishing-point. It was, indeed, owing to this latter circumstance that in a year or two his aspirations necessitated an increase of revenue; and a consequent determination to earn some money for himself led to his first real commercial enterprise as "candy butcher" on the Grand Trunk Railroad, already mentioned in a previous chapter. It has also been related how his precious laboratory was transferred to the train; how he and it were subsequently expelled; and how it was re-established in his home, where he continued studies and experiments until the beginning of his career as a telegraph operator.

The nomadic life of the next few years did not lessen his devotion to study; but it stood seriously in the way of satisfying the ever-present craving for a laboratory. The lack of such a place never prevented experimentation, however, as long as he had a dollar in his pocket and some available "hole in the wall." With the turning of the tide of fortune that suddenly carried him, in New York in 1869, from poverty to the opulence of $300 a month, he drew nearer to a realization of his cherished ambition in having money, place, and some time (stolen from sleep) for more serious experimenting. Thus matters continued until, at about the age of twenty-two, Edison's inventions had brought him a relatively large sum of money, and he became a very busy manufacturer, and lessee of a large shop in Newark, New Jersey.

Now, for the first time since leaving that boyish laboratory in the old home at Port Huron, Edison had a place of his own to work in, to think in; but no one in any way acquainted with Newark as a swarming centre of miscellaneous and multitudinous industries would recommend it as a cloistered retreat for brooding reverie and introspection, favorable to creative effort. Some people revel in surroundings of hustle and bustle, and find therein no hindrance to great accomplishment. The electrical genius of Newark is Edward Weston, who has thriven amid its turmoil and there has developed his beautiful instruments of precision; just as Brush worked out his arc-lighting system in Cleveland; or even as Faraday, surrounded by the din and roar of London, laid the intellectual foundations of the whole modern science of dynamic electricity. But Edison, though deaf, could not make too hurried a retreat from Newark to Menlo Park, where, as if to justify his change of base, vital inventions soon came thick and fast, year after year. The story of Menlo has been told in another chapter, but the point was not emphasized that Edison then, as later, tried hard to drop manufacturing. He would infinitely rather be philosopher than producer; but somehow the necessity of manufacturing is constantly thrust back upon him by a profound—perhaps finical—sense of dissatisfaction with what other people make for him. The world never saw a man more deeply and desperately convinced that nothing in it approaches perfection. Edison is the doctrine of evolution incarnate, applied to mechanics. As to the removal from Newark, he may be allowed to tell his own story: "I had a shop at Newark in which I manufactured stock tickers and such things. When I moved to Menlo Park I took out only the machinery that would be necessary for experimental purposes and left the manufacturing machinery in the place. It consisted of many milling machines and other tools for duplicating. I rented this to a man who had formerly been my bookkeeper, and who thought he could make money out of manufacturing. There was about $10,000 worth of machinery. He was to pay me $2000 a year for the rent of the machinery and keep it in good order. After I moved to Menlo Park, I was very busy with the telephone and phonograph, and I paid no attention to this little arrangement. About three years afterward, it occurred to me that I had not heard at all from the man who had rented this machinery, so I thought I would go over to Newark and see how things were going. When I got there, I found that instead of being a machine shop it was a hotel! I have since been utterly unable to find out what became of the man or the machinery." Such incidents tend to justify Edison in his rather cynical remark that he has always been able to improve machinery much quicker than men. All the way up he has had discouraging experiences. "One day while I was carrying on my work in Newark, a Wall Street broker came from the city and said he was tired of the 'Street,' and wanted to go into something real. He said he had plenty of money. He wanted some kind of a job to keep his mind off Wall Street. So we gave him a job as a 'mucker' in chemical experiments. The second night he was there he could not stand the long hours and fell asleep on a sofa. One of the boys took a bottle of bromine and opened it under the sofa. It floated up and produced a violent effect on the mucous membrane. The broker was taken with such a fit of coughing he burst a blood-vessel, and the man who let the bromine out got away and never came back. I suppose he thought there was going to be a death. But the broker lived, and left the next day; and I have never seen him since, either." Edison tells also of another foolhardy laboratory trick of the same kind: "Some of my assistants in those days were very green in the business, as I did not care whether they had had any experience or not. I generally tried to turn them loose. One day I got a new man, and told him to conduct a certain experiment. He got a quart of ether and started to boil it over a naked flame. Of course it caught fire. The flame was about four feet in diameter and eleven feet high. We had to call out the fire department; and they came down and put a stream through the window. That let all the fumes and chemicals out and overcame the firemen; and there was the devil to pay. Another time we experimented with a tub full of soapy water, and put hydrogen into it to make large bubbles. One of the boys, who was washing bottles in the place, had read in some book that hydrogen was explosive, so he proceeded to blow the tub up. There was about four inches of soap in the bottom of the tub, fourteen inches high; and he filled it with soap bubbles up to the brim. Then he took a bamboo fish-pole, put a piece of paper at the end, and touched it off. It blew every window out of the place."

Always a shrewd, observant, and kindly critic of character, Edison tells many anecdotes of the men who gathered around him in various capacities at that quiet corner of New Jersey—Menlo Park—and later at Orange, in the Llewellyn Park laboratory; and these serve to supplement the main narrative by throwing vivid side-lights on the whole scene. Here, for example, is a picture drawn by Edison of a laboratory interlude—just a bit Rabelaisian: "When experimenting at Menlo Park we had all the way from forty to fifty men. They worked all the time. Each man was allowed from four to six hours' sleep. We had a man who kept tally, and when the time came for one to sleep, he was notified. At midnight we had lunch brought in and served at a long table at which the experimenters sat down. I also had an organ which I procured from Hilbourne Roosevelt—uncle of the ex-President—and we had a man play this organ while we ate our lunch. During the summertime, after we had made something which was successful, I used to engage a brick-sloop at Perth Amboy and take the whole crowd down to the fishing-banks on the Atlantic for two days. On one occasion we got outside Sandy Hook on the banks and anchored. A breeze came up, the sea became rough, and a large number of the men were sick. There was straw in the bottom of the boat, which we all slept on. Most of the men adjourned to this straw very sick. Those who were not got a piece of rancid salt pork from the skipper, and cut a large, thick slice out of it. This was put on the end of a fish-hook and drawn across the men's faces. The smell was terrific, and the effect added to the hilarity of the excursion.

"I went down once with my father and two assistants for a little fishing inside Sandy Hook. For some reason or other the fishing was very poor. We anchored, and I started in to fish. After fishing for several hours there was not a single bite. The others wanted to pull up anchor, but I fished two days and two nights without a bite, until they pulled up anchor and went away. I would not give up. I was going to catch that fish if it took a week."

This is general. Let us quote one or two piquant personal observations of a more specific nature as to the odd characters Edison drew around him in his experimenting. "Down at Menlo Park a man came in one day and wanted a job. He was a sailor. I hadn't any particular work to give him, but I had a number of small induction coils, and to give him something to do I told him to fix them up and sell them among his sailor friends. They were fixed up, and he went over to New York and sold them all. He was an extraordinary fellow. His name was Adams. One day I asked him how long it was since he had been to sea, and he replied two or three years. I asked him how he had made a living in the mean time, before he came to Menlo Park. He said he made a pretty good living by going around to different clinics and getting $10 at each clinic, because of having the worst case of heart-disease on record. I told him if that was the case he would have to be very careful around the laboratory. I had him there to help in experimenting, and the heart-disease did not seem to bother him at all.

"It appeared that he had once been a slaver; and altogether he was a tough character. Having no other man I could spare at that time, I sent him over with my carbon transmitter telephone to exhibit it in England. It was exhibited before the Post-Office authorities. Professor Hughes spent an afternoon in examining the apparatus, and in about a month came out with his microphone, which was absolutely nothing more nor less than my exact invention. But no mention was made of the fact that, just previously, he had seen the whole of my apparatus. Adams stayed over in Europe connected with the telephone for several years, and finally died of too much whiskey—but not of heart-disease. This shows how whiskey is the more dangerous of the two.

"Adams said that at one time he was aboard a coffee-ship in the harbor of Santos, Brazil. He fell down a hatchway and broke his arm. They took him up to the hospital—a Portuguese one—where he could not speak the language, and they did not understand English. They treated him for two weeks for yellow fever! He was certainly the most profane man we ever had around the laboratory. He stood high in his class."

And there were others of a different stripe. "We had a man with us at Menlo called Segredor. He was a queer kind of fellow. The men got in the habit of plaguing him; and, finally, one day he said to the assembled experimenters in the top room of the laboratory: 'The next man that does it, I will kill him.' They paid no attention to this, and next day one of them made some sarcastic remark to him. Segredor made a start for his boarding-house, and when they saw him coming back up the hill with a gun, they knew there would be trouble, so they all made for the woods. One of the men went back and mollified him. He returned to his work; but he was not teased any more. At last, when I sent men out hunting for bamboo, I dispatched Segredor to Cuba. He arrived in Havana on Tuesday, and on the Friday following he was buried, having died of the black vomit. On the receipt of the news of his death, half a dozen of the men wanted his job, but my searcher in the Astor Library reported that the chances of finding the right kind of bamboo for lamps in Cuba were very small; so I did not send a substitute."

Another thumb-nail sketch made of one of his associates is this: "When experimenting with vacuum-pumps to exhaust the incandescent lamps, I required some very delicate and close manipulation of glass, and hired a German glass-blower who was said to be the most expert man of his kind in the United States. He was the only one who could make clinical thermometers. He was the most extraordinarily conceited man I have ever come across. His conceit was so enormous, life was made a burden to him by all the boys around the laboratory. He once said that he was educated in a university where all the students belonged to families of the aristocracy; and the highest class in the university all wore little red caps. He said HE wore one."

Of somewhat different caliber was "honest" John Kruesi, who first made his mark at Menlo Park, and of whom Edison says: "One of the workmen I had at Menlo Park was John Kruesi, who afterward became, from his experience, engineer of the lighting station, and subsequently engineer of the Edison General Electric Works at Schenectady. Kruesi was very exact in his expressions. At the time we were promoting and putting up electric-light stations in Pennsylvania, New York, and New England, there would be delegations of different people who proposed to pay for these stations. They would come to our office in New York, at '65,' to talk over the specifications, the cost, and other things. At first, Mr. Kruesi was brought in, but whenever a statement was made which he could not understand or did not believe could be substantiated, he would blurt right out among these prospects that he didn't believe it. Finally it disturbed these committees so much, and raised so many doubts in their minds, that one of my chief associates said: 'Here, Kruesi, we don't want you to come to these meetings any longer. You are too painfully honest.' I said to him: 'We always tell the truth. It may be deferred truth, but it is the truth.' He could not understand that."

Various reasons conspired to cause the departure from Menlo Park midway in the eighties. For Edison, in spite of the achievement with which its name will forever be connected, it had lost all its attractions and all its possibilities. It had been outgrown in many ways, and strange as the remark may seem, it was not until he had left it behind and had settled in Orange, New Jersey, that he can be said to have given definite shape to his life. He was only forty in 1887, and all that he had done up to that time, tremendous as much of it was, had worn a haphazard, Bohemian air, with all the inconsequential freedom and crudeness somehow attaching to pioneer life. The development of the new laboratory in West Orange, just at the foot of Llewellyn Park, on the Orange Mountains, not only marked the happy beginning of a period of perfect domestic and family life, but saw in the planning and equipment of a model laboratory plant the consummation of youthful dreams, and of the keen desire to enjoy resources adequate at any moment to whatever strain the fierce fervor of research might put upon them. Curiously enough, while hitherto Edison had sought to dissociate his experimenting from his manufacturing, here he determined to develop a large industry to which a thoroughly practical laboratory would be a central feature, and ever a source of suggestion and inspiration. Edison's standpoint to-day is that an evil to be dreaded in manufacture is that of over-standardization, and that as soon as an article is perfect that is the time to begin improving it. But he who would improve must experiment.