 CHAPTER XI. The Invention of the Incandescent Lamp It is possible to imagine a time to come when the hours of work and rest will once more be regulated by the sun. But the course of civilization has been marked by an artificial lengthening of the day and by a constant striving after more perfect means of illumination. Why mankind should sleep through several hours of sunlight in the morning and stay awake through a needless time in the evening can probably only be attributed to total depravity. It is certainly a most stupid, expensive and harmful habit, and no one thing has man-shown greater fertility of invention than in lighting. To nothing does he cling more tenaciously than to his devices for furnishing light. Electricity today reigns supreme in the field of illumination, but every other kind of artificial light that has ever been known is still in use somewhere. Toward its lightbringers the race has assumed an attitude of veneration, though it has forgotten, if it ever heard, the names of those who first brightened its gloom and dissipated its darkness. If the tallow candle hitherto unknown were now invented its creator would be hailed as one of the greatest benefactors of the present age. Up to the close of the eighteenth century the means of house and street illumination were of two generic kinds, grease and oil, but then came a swift and revolutionary change in the adoption of gas. The ideas and methods of Murdoch and Leban soon took definite shape and coal smoke was piped from its place of origin to distant points of consumption. As early as 1804 the first company ever organized for gaslighting was formed in London, one side of Paul Mall being lit up by the enthusiastic pioneer, Windsor, in 1807. Equal activity was shown in America, and Baltimore began the practice of gaslighting in 1816. It is true that there were explosions, and distinguished men like Davy and Watt opined that the illuminate was too dangerous, but the spirit of coal has demonstrated its usefulness convincingly, and a commercial development began which, for extent and rapidity, was not inferior to that marking the concurrent adoption of steam in industry and transportation. Meanwhile, the wax candle and the argund oil lamp held their own bravely. The whaling fleets long after gas came into use were one of the greatest sources of our national wealth. To New Benford, Massachusetts alone some three or four hundred ships brought their whale and sperm oil, spermaceti and whale bone, and at one time that port was accounted the richest city in the United States in proportion to its population. The ship owners and refiners of that whaling metropolis were slow to believe that their monopoly could ever be threatened by newer sources of illumination, but gas had become available in the cities, and coal oil and petroleum were now added to the list of illuminating materials. The American whaling fleet, which at the time of Edison's birth mustered over seven hundred sail, had dwindled probably to a bare tenth when he took up the problem of illumination, and the competition of oil from the ground with oil from the sea and with coal gas had made the artificial production of light cheaper than ever before. When up to the middle of the century it had remained one of the heaviest items of domestic expense. Moreover, just about the time that Edison took up incandescent lighting, water gas was being introduced on a large scale as a commercial illuminate that could be produced at much lower costs than coal gas. Throughout the first half of the nineteenth century the search for a practical electric light was almost wholly in the direction of employing methods analogous to those already familiar, in other words obtaining the illumination from the actual consumption of the light-giving material. In the third quarter of the century these methods were brought to practicality, but all may be referred back to the brilliant demonstrations of Sir Humphrey Davy at the Royal Institution circa 1809 and 10, when, with the current from a battery of two thousand cells, he produced an intense voltaic arc between the points of consuming sticks of charcoal. For more than thirty years the arc light remained an expensive laboratory experiment, but the coming of the dynamo placed that illuminate on a commercial basis. The mere fact that electrical energy from the least expensive chemical battery using up zinc and acids cost twenty times as much as that from a dynamo driven by steam engine is in itself enough to explain why so many of the electric arts lingered in embryo after their fundamental principles had been discovered. Here is seen also further proof of the great truth that one invention often waits for another. From 1850 onward the improvements in both the arc lamp and the dynamo were rapid and under the superintendents of the great Faraday in 1858 protecting beams of intense electric light from the voltaic arc were shed over the waters of the Straits of Dover from the beacons of South Forland and Dungeonus. By 1878 the arc lighting industry had sprung into existence in so promising a manner as to engender an extraordinary fever and furor of speculation. At the Philadelphia Centennial Exposition of 1876 Wallace Farmer Dynamos built at Ansonia, Connecticut were shown. With the current from which arc lamps were there put in actual service. A year or two later the work of Charles F. Brush and Edward Weston laid the deep foundation of modern arc lighting in America securing as well substantial recognition abroad. Thus the new era had been ushered in, but it was based altogether on the consumption of some material, carbon, in a lamp open to the air. Every lamp the world had ever known did this in one way or another. Edison himself began at that point and his notebooks show that he made various experiments with this type of lamp at a very early stage. Indeed his experiments had led him so far as to anticipate in 1875 what are now known as flaming arcs. The exceedingly bright and generally orange or rose colored lights which have been introduced within the last few years and are now so frequently seen in streets and public places. While the arcs with plain carbons are bluish white those with carbons containing calcium fluoride have a notable golden glow. He was convinced, however, that the greatest field of lighting lay in the illumination of houses and other comparatively enclosed areas to replace the ordinary gas light rather than in the illumination of streets and other outdoor places by lights of great volume and brilliancy. Dismissing from his mind quickly the commercial impossibility of using arc lights for general indoor illumination he arrived at the conclusion that an electric lamp giving light by incandescence was the solution of the problem. Edison was familiar with the numerous but impracticable and commercially unsuccessful efforts that had been previously made by other inventors and investigators to produce electric light by incandescence, and at the time that he began his experiments in 1877 almost the whole scientific world had pronounced such an idea as impossible of fulfillment. The leading electricians, physicists, and experts of the period had been studying the subject for more than a quarter of a century and with but one known exception had proven mathematically and by close reasoning that the subdivision of the electric light as it was then termed was practically beyond attainment. Opinions of this nature have ever been but a stimulus to Edison when he has given deep thought to a subject and has become impressed with strong convictions of possibility, and in this particular case he was satisfied that the subdivision of the electric light or more correctly the subdivision of the electric current was not only possible but entirely practicable. It will have to be perceived from the foregoing chapters that from the time of boyhood when he first began to rub against the world his commercial instincts were alert and predominated in almost all of the enterprises that he set in motion. This characteristic trait had grown stronger as he matured, having received as it did fresh impetus and strength from his one lapse in the case of his first patented invention, the vote recorder. The lesson he then learned was to devote his inventive faculties only to things for which there was a real, genuine demand, and that would subserve the actual necessities of humanity, and it was probably a fortunate circumstance that this lesson was learned at the outset of his career as an inventor. He has never assumed to be a philosopher or pure scientist. In order that the reader may grasp an adequate idea of the magnitude and importance of Edison's invention of the incandescent lamp it will be necessary to review briefly the state of the art at the time he began his experiments on that line. After the invention of the voltaic battery early in the last century experiments were made which determined that heat could be produced by the passage of the electric current through wires of platinum and other metals and through pieces of carbon as noted already, and it was, of course, also observed that if sufficient current were passed through these conductors they could be brought from the lower stage of redness up to the brilliant white heat of incandescence. As early as 1845 the results of these experiments were taken advantage of when Star, a talented American who died at the early age of twenty-five, suggested in his English patent of that year two forms of small incandescent electric lamps, one having a burner made from platinum foil placed under a glass cover without excluding the air, and the other composed of a thin plate or pencil of carbon enclosed in a Turacellian vacuum. These suggestions of young Star were followed by many other experimenters whose improvements consisted principally in devices to increase the compactness and portability of the lamp in the sealing of the lamp chamber to prevent the emission of air and in the means for renewing the carbon burner when it had been consumed. Thus Roberts, in 1852, proposed to cement the neck of the glass globe into a metallic cup and to provide it with a tube or stopcock for exhaustion by means of a hand pump. Lodigwein, Kahn, Kossloff, and Kotinsky between 1872 and 1877, proposed various ingenious devices for perfecting the joint between the metal base and the glass globe, and also provided their lamps with several short carbon pencils which were automatically brought into circuit successively as the pencils were consumed. In 1876 or 1877, Blingwein proposed the employment of a long carbon pencil, a short section only of which was in circuit at any one time, and formed the burner. The lamp being provided with a mechanism for automatically pushing other sections of the pencil into position between the contacts to renew the burner. Sawyer and Mann proposed in 1878 to make the bottom plate of glass instead of metal and provided ingenious arrangements for charging the lamp chamber with an atmosphere of pure nitrogen gas which does not support combustion. These lamps and many others of similar character, ingenious as they were, failed to become of any commercial value due, among other things, to the brief life of the carbon burner. Even under the best conditions, it was found that the carbon members were subject to a rapid disintegration or evaporation which experimenters assumed was due to the disrupting action of the electric current, and hence the conclusion that carbon contained in itself the elements of its own destruction and was not a suitable material for the burner of an incandescent lamp. On the other hand, Platinum, although found to be the best of all materials for the purpose, aside from its great expense and not combining with oxygen at high temperatures as this carbon, required to be brought so near the melting point in order to give light that a very slight increase in the temperature resulted in its destruction. It was assumed that the difficulty lay in the material of the burner itself and not in its environment. It was not realized up to such a comparatively recent date as 1879 that the solution of the great problem of subdivision of the electric current would not, however, be found merely in the production of a durable incandescent electric lamp, even if any of the lamps above referred to had fulfilled that requirement. The other principal features necessary to subdivide the electric current successfully were the burning of an indefinite number of lights on the same circuit, each light to give a useful and economical degree of illumination, and each light to be independent of all the others in regard to its operation and extinguishment. The opinions of scientific men of the period on the subject are well represented by the two following extracts, the first from a lecture at the Royal United Service Institution about February 1879 by Mr. Sir W. Priest, one of the most eminent electricians in England, who, after discussing the question mathematically, said, hence the subdivision of the light is an absolute ignis fatuus. The other extract is from a book written by Paget Higgs, LLD, Doctor of Science, published in London in 1879, in which he says, much nonsense has been talked in relation to this subject. Some inventors have claimed the power to indefinitely divide the electric current, not knowing or forgetting that such a statement is incompatible with the well-proven law of conservation of energy. Some inventors, in the last sentence just quoted, probably, indeed we think undoubtedly refers to Edison, whose earlier work in electric lighting, 1878, had been announced in this country and abroad, and who had then stated boldly his conviction of the practicability of the subdivision of the electric current. The above extracts are good illustrations, however, of scientific opinions up to the end of 1879, when Mr. Edison's epic-making invention rendered them entirely untenable. The eminent scientist John Tyndall, while not sharing these precise views, at least as late as January 17th, 1879, delivered a lecture before the royal institution on the electric light, when after pointing out the development of the art up to Edison's work and showing the apparent hopelessness of the problem, he said, knowing something of the intricacy of the practical problem, I should certainly prefer seeing it in Edison's hands to having it in mine. The reader may have deemed this sketch of the state of the art to be a considerable digression, but it is certainly due to the subject to present the facts in such a manner as to show that this great invention was neither the result of improving some process or device that was known or existing at the time, nor due to any unforeseen lucky chance, nor the accidental result of other experiments. On the contrary, it was the legitimate outcome of a series of exhaustive experiments founded upon logical and original reasoning in a mind that had the courage and hardy-hood to set at naught the confirmed opinions of the world, voiced by those generally acknowledged to be the best exponents of the art. Experiments carried on amid a storm of jeers and derision, almost as contemptuous as if the search were for the discovery of perpetual motion. In this we see the man foreshadowed by the boy, who, when he obtained his books on chemistry or physics, did not accept any statement of fact or experiment therein, but worked out every one of them himself to ascertain whether or not they were true. Although this brings the reader up to the year 1879, one must turn back two years and accompany Edison in his first attack on the electric light problem. In 1877 he sold his telephone invention, the Carbon Transmitter, to the Western Union Telegraph Company, which had previously come into possession also of his quadruplex inventions, as already related. He was still busily engaged on the telephone, on acoustic electrical transmission, sextuplex telegraphs, duplex telegraphs, miscellaneous carbon articles, and other inventions of a minor nature. During the whole of the previous year, and until late in the summer of 1877, he had been working with characteristic energy and enthusiasm on the telephone. And in developing this invention to a successful issue, had preferred the use of carbon and had employed it in numerous forms, especially in the form of carbonized paper. 1877 in Edison's laboratory was a veritable carbon year, for it was carbon in some shape or form for interpolation in electric circuits of various kinds that occupied the thoughts of the whole force from morning to night. It is not surprising therefore that in September of that year, when Edison turned his thoughts actively toward electric lighting by incandescence, his early experiment should be in the line of carbon as an illuminant. His originality of method was displayed at the very outset, for one of the first experiments was the bringing of incandescence of a strip of carbon in the open air to ascertain merely how much current was required. This conductor was a strip of carbonized paper about an inch long, one sixteenth of an inch broad, and six or seven one thousandths of an inch thick, the ends of which were secured to clamps that formed the poles of a battery. The carbon was lighted up to incandescence and, of course, oxidized and disintegrated immediately. Within a few days this was followed by experiments with the same kind of carbon, but in vacuo, by means of a handworked air pump. This time the carbon strip burned at incandescence for about eight minutes. Various experiments to prevent oxidation were tried, such, for instance, as coating the carbon with powdered glass, which in melting would protect the carbon from the atmosphere, but without successful results. Edison was inclined to concur in the prevailing opinion as to the easy destructibility of carbon, but without actually settling the point in his mind, he laid aside temporarily this line of experiment and entered a new field. He had made previously some trials of platinum wire as an incandescent burner for a lamp, but left it for a time in favor of carbon. He now turned to the use of almost infusible metals, such as boron, ruthenium, chromium, etc., as separators or tiny bridges between two carbon points. The current acting so as to bring these separators to a high degree of incandescence at which point they would emit a brilliant light. He also placed some of these refractory metals directly in the circuit, bringing them to incandescence, and used silicon in powdered form and glass tubes placed in the electric circuit. His notes include the use of powdered silicon mixed with lime or other very infusible nonconductors or semiconductors. Edison's conclusions on these substances were that, while in some respects they were within the boundaries of possibility for the subdivision of the electric current, they did not reach the ideal that he had in mind for commercial results. Edison's systematized attacks on the problem were two in number, the first of which we have just related, which began in September 1877, and continued until about January 1878. Contemporaneously, he and his force of men were very busily engaged day and night on other important enterprises and inventions. Among the latter, the phonograph may be specially mentioned, as it was invented in the late fall of 1877. From that time until July 1878, his time and attention day and night were almost completely absorbed by the excitement caused by the invention and exhibition of the machine. In July, feeling entitled to a brief vacation after several years of continuous labor, Edison went with the expedition to Wyoming to observe an eclipse of the sun and, incidentally, to test his tazimeter, a delicate instrument devised by him for measuring heat transmitted through immense distances of space. His trip has been already described. He was absent about two months. Coming home, rested and refreshed, Mr. Edison says, after my return from the trip to observe the eclipse of the sun, I went with Professor Barker, Professor of Physics in the University of Pennsylvania, and Dr. Chandler, Professor of Chemistry in Columbia College, to see Mr. Wallace, a large manufacturer of brass in Ansonia, Connecticut. Wallace at this time was experimenting on Ceres arc lighting. Just at that time, I wanted to take up something new, and Professor Barker suggested that I go to work and see if I could subdivide the electric light, so it could be got in small units like gas. This was not a new suggestion, because I had made a number of experiments on electric lighting a year before this. They had been laid aside for the phonograph. I determined to take up the search again and continue it. On my return home, I started my usual course of collecting every kind of data about gas, bought all the transactions of the gas engineering societies, etc., all the back volumes of gas journals, etc. Having obtained all the data and investigated gas jet distribution in New York by actual observations, I made up my mind that the problem of the subdivision of the electric current could be solved and made commercial. About the end of August, 1878, he began his second organized attack on the subdivision of the current, which was steadily maintained until he achieved signal victory a year and two months later. The date of this interesting visit to Ansonia is fixed by an inscription made by Edison on a glass goblet which he used. The legend in Diamond Scratches runs. Thomas A. Edison, September 8th, 1878, made under the electric light. Other members of the party left similar memorials, which under the circumstances have come to be greatly prized. A number of experiments were witnessed in arc lighting, and Edison secured a small Wallace farmer dynamo for his own work, as well as a set of Wallace arc lamps for lighting the Menlo Park Laboratory. Before leaving Ansonia, Edison remarked significantly, Wallace, I believe I can beat you making electric lights. I don't think you are working in the right direction. Another date which shows how promptly the work was resumed is October 14th, 1878, when Edison filed an application for his first lighting patent, improvement in electric lights. And after years, discussing the work of Wallace, who was not only a great pioneer, electrical manufacturer, but one of the founders of the wire drawing and brassworking industry, Edison said, Wallace was one of the earliest pioneers in electrical matters in this country. He has done a great deal of good work, for which others have received the credit, and the work which he did in the early days of electric lighting, others have benefited by largely, and he has been crowded to one side and forgotten. Associated in all this work with Wallace at Ansonia was Professor Moses G. Farmer, famous for the introduction of the fire alarm system, as the discoverer of the self-exciting principle of the modern dynamo, as a pioneer experimenter in the electric railway field, as a telegraph engineer, and as a lecturer on mines and explosives to naval classes at Newport. During 1858, Farmer, who like Edison was a ceaseless investigator, had made a series of studies upon the production of light by electricity, and had even invented an automatic regulator, by which a number of platinum lamps in multiple arc could be kept at uniform voltage for any length of time. In July 1859, he lit up one of the rooms of his house at Salem, Massachusetts, every evening with such lamps, using in them small pieces of platinum and iridium wire, which were made to incandesse by means of current from primary batteries. Farmer was not one of the party that memorable day in September, but his work was known through his intimate connection with Wallace, and there is no doubt that reference was made to it. Such work had not led very far. The lamps were hopelessly short-lived, and everything was obviously experimental, but it was all helpful and suggestive to one whose open mind refused no hint from any quarter. At the commencement of his new attempts, Edison returned to his experiments with carbon as an incandescent burner for a lamp, and made a very large number of trials all in vacuo. Not only were the ordinary strip paper carbons tried again, but tissue paper coated with tar and lamp black was rolled into thin sticks like knitting needles, carbonized and raised to incandescence in vacuo. Edison also tried hard carbon, wood carbons, and almost every conceivable variety of paper carbon in like manner. With the best vacuum that he could then get by means of the ordinary air pump, the carbons would last at the most, only from ten to fifteen minutes in a state of incandescence. Such results were evidently not of commercial value. Edison then turned his attention in other directions. In his earliest consideration of the problem of subdividing the electric current, he had decided that the only possible solution lay in the employment of a lamp whose incandescing body should have a high resistance combined with a small radiating surface and be capable of being used in what is called multiple arc so that each unit or lamp could be turned on or off without interfering with any other unit or lamp. No other arrangement could possibly be considered as commercially practicable. The full significance of the last three preceding sentences will not be obvious to laymen, as undoubtedly many of the readers of this book may be. And now being on the threshold of the series of Edison's experiments that led up to the basic invention, we interpolate a brief explanation in order that the reader may comprehend the logical reasoning and work that in this case produced such far-reaching results. If we consider a simple circuit in which a current is flowing and include in the circuit a carbon horseshoe-like conductor, which it is desired to bring to incandescence by the heat generated by the current passing through it, it is first evident that the resistance offered to the current by the wires themselves must be less than that offered by the burner, because otherwise current would be wasted as heat in the conducting wires. At the very foundation of the electric lighting art is the essentially commercial consideration that one cannot spend very much for conductors and Edison determined that in order to use wires of a practicable size, the voltage of the current, that is its pressure or the characteristic that overcomes resistance to its flow, should be 110 volts, which since its adoption has been the standard. To use a lower voltage or pressure while making the solution of the lighting problem a simple one, as we shall see, would make it necessary to increase the size of the conducting wires to a prohibitive extent. To increase the voltage or pressure materially, while permitting some saving in the cost of conductors, would enormously increase the difficulties of making a sufficiently high resistance conductor to secure light by incandescence. This apparently remote consideration, weight of copper used, was really the commercial key to the problem, just as the incandescent burner was the scientific key to that problem. Before Edison's invention, incandescent lamps had been suggested as a possibility, but they were provided with carbon rods or strips of relatively low resistance, and to bring these to incandescence required a current of low pressure because a current of high voltage would pass through them so readily as not to generate heat, and to carry a current of low pressure through wires without loss would require wires of enormous size. Having a current of relatively high pressure to contend with, it was necessary to provide a carbon burner which, as compared with what had previously been suggested, should have a very great resistance. Carbon as a material, determined after patient search, apparently offered the greatest hope, but even with this substance, the necessary high resistance would be obtained only by making the burner of extremely small cross-section, thereby also reducing its radiating surface. Therefore, the crucial point was the production of a hair-like carbon filament, with a relatively great resistance and small radiating surface capable of withstanding mechanical shock and susceptible of being maintained at a temperature of over 2000 degrees for a thousand hours or more before breaking. And this filamentary conductor required to be supported in a vacuum chamber, so perfectly formed and constructed, that during all those hours and subjected as it is to varying temperatures, not a particle of air should enter to disintegrate the filament. And not only so, but the lamp after its design must not be a mere laboratory possibility, but a practical commercial article capable of being manufactured at low cost and in large quantities. A statement of what had to be done in those days of actual as well as scientific electrical darkness is quite sufficient to explain Tyndall's attitude of mind and preferring that the problem should be in Edison's hands rather than in his own. To say that the solution of the problem lay merely in reducing the size of the carbon burner to a mere hair is to state a half-truth only, but who, we asked, would have had the temerity even to suggest that such an attenuated body could be maintained at a white heat without disintegration for a thousand hours. The solution consisted not only in that, but in the enormous mass of patiently worked-out details, the manufacture of the filaments, their uniform carbonization, making the globes, producing a perfect vacuum, and countless other factors, the emission of any of which would probably have resulted eventually in failure. Footnote 8. As a practical illustration of these facts, it was calculated by Professor Barker at the University of Pennsylvania after Edison had invented the incandescent lamp, that if it should cost $100,000 for copper conductors to supply current to Edison lamps in a given area, it would cost about $200 million for copper conductors for lighting the same area by lamps of the earlier experimenters, such, for instance, as the lamp invented by Kahn in 1875. This enormous difference would be accounted for by the fact that Edison's lamp was one having a high resistance and relatively small radiating surface, while Kahn's lamp was one having a very low resistance and large radiating surface. Continuing the digression one step farther in order to explain the term multiple arc, it may be stated that there are two principal systems of distributing electric current, one termed series and the other multiple arc. The two are illustrated diagrammatically side by side, the arrows indicating flow of current, the series system it will be seen, presents one continuous path for the current. The current for the last lamp must pass through the first and all the intermediate lamps. Hence, if any one light goes out, the continuity of the path is broken, current cannot flow and all the lamps are extinguished unless a loop or bypass is provided. It is quite obvious that such a system would be commercially impracticable where small units, similar gas jets, were employed. On the other hand, in the multiple arc system, current may be considered as flowing in two parallel conductors, like the vertical sides of the ladder, the ends of which never come together. Each lamp is placed in a separate circuit across these two conductors, like a rung in the ladder, thus making a separate and independent path for the current in each case. Hence, if a lamp goes out, only that individual subdivision or ladder step is affected. Just that one particular path for the current is interrupted, but none of the other lamps is interfered with. They remain lighted, each one independent of the other. The reader will quite readily understand therefore that a multiple arc system is the only one practically commercial where electric light is to be used in small units, like those of gas or oil. Such was the nature of the problem that confronted Edison at the outset. There was nothing in the whole world that in any way approximated a solution, although the most brilliant minds in the electrical art had been assiduously working on the subject for a quarter of a century proceeding. As already seen, he came early to the conclusion that the only solution lay in the use of a lamp of high resistance and small radiating surface, and with characteristic fervor and energy he attacked the problem from this standpoint, having absolute faith in a successful outcome. The mere fact that even with the successful production of the electric lamp the assault on the complete problem of commercial lighting would hardly be begun did not deter him in the slightest. To one of Edison's enthusiastic self-confidence, the long vista of difficulties ahead, we say it in all sincerity, must have been alluring. After having devoted several months to experimental trials of carbon, at the end of 1878, as already detailed, he turned his attention to the platinum group of metals and began a series of experiments in which he used chiefly platinum wire and iridium wire and alloys of refractory metals in the form of wire burners for incandescent lamps. These metals have very high fusing points and were found to last longer than the carbon strips previously used, when heated up to incandescence by the electric current. Although under such conditions as were then possible, they were melted by excess of current after they had been lighted at comparatively short time, either in the open air or in such a vacuum as could be obtained by means of the ordinary air pump. Nevertheless, Edison continued along this line of experiment with unremitting vigor, making improvement after improvement. Until about April 1879 he devised a means whereby platinum wire of a given length, which would melt in the open air when giving a light equal to four candles, would emit a light of 25 candle power without fusion. This was accomplished by introducing the platinum wire into an all glass globe completely sealed and highly exhausted of air and passing a current through the platinum wire while the vacuum was being made. In this, which was a new and radical invention, we see the first step toward the modern incandescent lamp. The knowledge thus obtained that current passing through the platinum during exhaustion would drive out occluded gases, that is, gases mechanically held in or upon the metal, and increase the infusibility of the platinum led him to aim at securing greater perfection in the vacuum, on the theory that the higher the vacuum obtained, the higher would be the infusibility of the platinum burner. And this fact also was of the greatest importance in making successful the final use of carbon, because without the subjection of the carbon to the heating effect of current, during the formation of the vacuum, the presence of occluded gases would have been a fatal obstacle. Continuing these experiments with most fervent zeal, taking no account of the passage of time, with an utter disregard for meals, and but scanty hours of sleep snatched reluctantly at odd periods of the day or night, Edison kept his laboratory going without cessation. A great variety of lamps was made of the platinum iridium type, mostly with thermal devices to regulate the temperature of the burner, and prevent its being melted by an excess of current. The study of apparatus for obtaining more perfect vacua was unceasingly carried on, for Edison realized that in this there lay a potent factor of ultimate success. About August he had obtained a pump that would produce a vacuum up to about one hundred thousandths part of an atmosphere, and sometime during the next month or beginning of October had obtained one that would produce a vacuum up to one millionth part of an atmosphere. It must be remembered that the conditions necessary for maintaining this high vacuum were only made possible by his invention of the one-piece all-glass globe in which all the joints were hermetically sealed during its manufacture into a lamp, whereby a high vacuum could be retained continuously for any length of time. In obtaining this perfection of vacuum apparatus Edison realized that he was approaching much nearer to a solution of the problem. In his experiments with the platinum iridium lamps he had been working all the time toward the proposition of high resistance and small radiating surface until he had made a lamp having 30 feet of fine platinum wire wound upon a small bobbin of infusible material, but the desired economy, simplicity, and durability were not obtained in this manner, although at all times the burner was maintained at a critically high temperature. After attaining a high degree of perfection with these lamps he recognized their impracticable character and his mind reverted to the opinion he had formed in his early experiments two years before, namely that carbon had the requisite resistance to permit a very simple conductor to accomplish the object if it could be used in the form of a hair-like filament provided the filament itself could be made sufficiently homogeneous. As we have already seen he could not use carbon successfully in his earlier experiments for the strips of carbon he then employed though they were much larger than filaments would not stand but were consumed in a few minutes under the imperfect conditions then at his command. Now however that he had found means for obtaining and maintaining high vacua Edison immediately went back to carbon which from the first he had conceived of as the ideal substance for a burner. His next step proved conclusively the correctness of his old deductions. On October 21st 1879 after many patient trials he carbonized a piece of cotton sewing thread bent into a loop or horseshoe form and had it sealed into a glass globe from which he exhausted the air until a vacuum up to one millionth of an atmosphere was produced. This lamp when put on the circuit lighted up brightly to incandescent and maintained its integrity for over 40 hours and low the practical incandescent lamp was born. The impossible so called had been attained. Subdivision of the electric light current was made practicable the goal had been reached and one of the greatest inventions of the century was completed. Up to this time Edison had spent over forty thousand dollars in his electric light experiments but the results far more than justified the expenditure for with this lamp he made the discovery that the filament of carbon under the conditions of high vacuum was commercially stable and would stand high temperatures without the disintegration and oxidation that took place in all previous attempts that he knew of for making an incandescent burner out of carbon. Besides this lamp possessed the characteristics of high resistance and small radiating surface permitting economy in the outlay for conductors and requiring only a small current for each unit of light conditions that were absolutely necessary a fulfillment in order to accomplish commercially the subdivision of the electric light current. This slender fragile tenuous thread of brittle carbon glowing steadily and continuously with a soft light agreeable to the eyes was the tiny key that opened the door to a world revolutionized in its interior illumination it was a triumphant vindication of Edison's reasoning powers his clear perceptions his insight into possibilities and his inventive faculty all of which had already been productive of so many startling practical and epic making inventions and now he had stepped over the threshold of a new art which has since become so worldwide in its application as to be an integral part of the modern human experience. footnote nine the following extract from Walker on patents will probably be of interest to the reader section 31a a meritorious exception to the rule of the last section is involved in the adjudicated validity of the Edison incandescent light patent the carbon filament which constitutes the only new part of the combination of the second claim of that patent differs from the earlier carbon burners of Sawyer and Mann only in having a diameter of one sixty-fourth of an inch or less whereas the burners of Sawyer and Mann had a diameter of one thirty-second of an inch or more but that reduction of one half in diameter increased the resistance of the burner fourfold and reduced its radiating surface to fold and thus increased eightfold its ratio of resistance to radiating surface that eightfold increase in proportion enable the resistance of the conductor of electricity from the generator to the burner to be increased eightfold without any increase of percentage of loss of energy in that conductor or decrease of percentage of development of heat in the burner and thus enable the area of the cross section of that conductor to be reduced eightfold and thus to be made with one eighth of the amount of copper or other metal which would be required if the reduction of diameter of the burner from one thirty-second to one sixty-fourth of an inch had not been made and that great reduction in the size and cost of conductors involved also a great difference in the composition of the electric energy employed in the system that difference consisting in generating the necessary amount of electrical energy was comparatively high electromotive force and comparatively low current instead of contrary wise for this reason the use of carbon filaments one sixty-fourth of an inch in diameter or less instead of carbon burners one thirty-second of an inch in diameter or more not only worked an enormous economy in conductors but also necessitated a great change in generators and did both according to a philosophy which Edison was the first to know and which is stated in this paragraph in its simplest form and aspect and which lies at the foundation of the incandescent electric lighting of the world no sooner had the truth of this new principle been established than the work to establish it firmly and commercially was carried out more assiduously than ever the next immediate step was a further investigation of the possibilities of improving the quality of the carbon filament Edison had previously made a vast number of experiments with carbonized paper for various electrical purposes with such good results that he once more turned to it and now made fine filament-like loops of this material which were put into other lamps these proved even more successful commercially considered than the carbonized thread so much so that after a number of such lamps had been made and put through severe tests the manufacture of lamps from these paper carbons was begun and carried on continuously this necessitated first the devising and making of a large number of special tools for cutting the carbon filaments and for making and putting together the various parts of the lamps meantime great excitement had been caused in this country and in Europe by the announcement of Edison's success in the old world scientists generally still declared the impossibility of subdividing the electric light current and in the public press Mr. Edison was denounced as a dreamer other names of a less complementary nature were applied to him even though his lamp were actually in use and the principle of commercial incandescent lighting had been established between October 21st, 1879 and December 21st, 1879 some hundreds of these paper carbon lamps had been made and put into actual use not only in the laboratory but in the streets and several residences at Menlo Park, New Jersey causing great excitement and bringing many visitors from far and near on the latter date a full-page article appeared in the New York Herald which so intensified the excited feeling that Mr. Edison deemed it advisable to make a public exhibition on New Year's Eve, 1879 special trains were run to Menlo Park by the Pennsylvania Railroad and over 3,000 persons took advantage of the opportunity to go out there and witness this demonstration for themselves in this great crowd were many public officials and men of prominence in all walks of life who were enthusiastic in their praises in the meantime the mind that conceived and made practical this invention could not rest content with anything less than perfection so far as it could be realized Edison was not satisfied with paper carbons they were not fully up to the ideal that he had in mind what he sought was a perfectly uniform and homogeneous carbon one like the one Haas Shea that had no weak spots to break down at inopportune times he began to carbonize everything in nature that he could lay his hands on and his laboratory notebooks are innumerable jottings of the things that were carbonized and tried such as tissue paper soft paper all kinds of cardboards drawing paper of all grades paper saturated with tar all kinds of threads fish line threads rubbed with tarred lamp black fine threads plated together in strands cotton soaked in boiling tar lampwick twine tar and lamp black mixed with a proportion of lime vulcanized fiber celluloid boxwood coconut hair and shell spruce hickory baywood cedar and maple shavings rosewood punk cork bagging flax and a host of other things he also extended his searches far into the realms of nature in the line of grasses plants canes and similar products and in these experiments at that time and later he carbonized made into lamps and tested no fewer than 6000 different species of vegetable growth the reasons for such prodigious research are not apparent on the face of the subject nor is this the occasion to enter into an explanation as that alone would be sufficient to fill a fair size book suffice it to say that Edison's omniferous reading keen observation power of assimilating facts and natural phenomena and skill in applying the knowledge thus attained to whatever was at hand now came into full play in determining that the results he desired could only be obtained in certain directions at this time he was investigating everything with a microscope and one day in the early part of 1880 he noticed upon a table in the laboratory an ordinary palm leaf fan he picked it up and looking it over observed that it had a binding rim made of bamboo cut from the outer edge of the cane a very long strip he examined this and then gave it to one of his assistants telling him to cut it up and get out of it all the filaments he could carbonize them put them into lamps and try them the results of this trial were exceedingly successful far better than with anything else thus far used indeed so much so that after further experiments and microscopic examinations Edison was convinced that he was now on the right track for making a thoroughly stable commercial lamp and shortly afterward he sent a man to Japan to procure further supplies of bamboo the fascinating story of the bamboo hunt will be told later but even this bamboo lamp was only one item of a complete system to be devised a system that has since completely revolutionized the art of interior illumination reference has been made in this chapter to the preliminary study that Edison brought to bear on the development of the gas art and industry this study was so exhaustive that one can only compare it to the careful investigation made in advance by any competent war staff of the elements of strength and weakness on both sides in a possible campaign a popular idea of Edison that dies hard pictures a breezy slap-dash energetic inventor arriving at new results by luck and intuition making boastful assertions and then winning out by mere chance the native simplicity of the man the absence of pose and ceremony do much to strengthen this notion but the real truth is that while gifted with unusual imagination Edison's march to the goal of a new invention is positively humdrum and monotonous in its steady progress no one ever saw Edison in a hurry no one ever saw him lazy and that which he did with slow careful scrutiny six months ago he will be doing with just as much calm deliberation of research six months hence and six years hence if necessary if for instance he were asked to find the most perfect pebble on the Atlantic shore of New Jersey instead of hunting here there and everywhere for the desired object we would no doubt find him patiently screening the entire beach sifting out the most perfect stones and eventually by gradual exclusion reaching the long sought for pebble and the mere fact that in this search years might be taken would not lessen his enthusiasm to the slightest extent in the prospectus book among the series of famous notebooks all the references and data apply to gas the book is numbered 184 falls into the period now dealt with and runs along casually with items spread out over two or three years all these notes refer specifically to electricity versus gas as general illuminance and cover an astounding range of inquiry and comment one of the very first notes tells the whole story object Edison to affect exact imitation of all done by gas so as to replace lighting by gas by lighting by electricity to improve the illumination to such an extent as to meet all requirements of natural artificial and commercial conditions a large program but fully executed the notes it will be understood are all in Edison's handwriting they go on to observe that a general system of distribution is the only possible means of economic illumination and they dismiss isolated plant lighting as in mills and factories as of so little importance to the public we shall leave the consideration of this out of this book the shrewd prophecy is made that gas will be manufactured less for lighting as the result of electrical competition and more and more for heating etc thus enlarging its market and increasing its income comment is made on kerosene and its cost and all kinds of general statistics are jotted down as desirable data are to be obtained on lamp and dynamo efficiency and another review of the whole thing is worked out upon pure science principles by Roland Young Trowbridge also Roland on the possibilities and probabilities of cheaper production by better manufacture higher incandescence without decrease of life in lamps notes are also made on meters and motors it doesn't matter if electricity is used for light or for power while small motors it is observed can be used night or day and small steam engines are inconvenient again the shrewd comment generally poorest district for light best for power thus evening up whole city the effect of this on investment it is pointed out that previous inventions failed necessities for commercial success and accomplishment by Edison Edison's great effort not to make a large light or a blinding light but a small light having the mildness of gas curves are then called for of iron and copper investment also energy line curves of candle power and electromotive force curves on motors graphic representation of the consumption of gas January to December tables in formulae representations graphically of what $1 will buy in different kinds of light table weight of copper require different distance 100 ohm lamp 16 candles table with curve showing increased economy by larger engine higher power etc there is not much that is diligent about all this note is made of an article in April 1879 putting the total amount of gas investment in the whole world at that time at $1,500,000,000,000 which is now 1910 about the amount of the electric lighting investment in the United States incidentally a note remarks so unpleasant is the effect of the products of gas that in the new Madison Square theater every gas jet is ventilated by special tubes to carry away the products of combustion in short there is no aspect of the new problem to which Edison failed to apply his acutus powers and the speed with which the new system was worked out and introduced was simply due to his initial mastery of all the factors in the older art Luther Steeringer an expert gas engineer and inventor whose services were early enlisted once said that Edison knew more about gas than any other man he had ever met the remark is an evidence of the kind of preparation Edison gave himself for his new task End of Chapter 11 Recording by Ralph Snelson, Springfield, Utah Edison his life and inventions by Frank Louis Dyer and Thomas Comerford Martin Chapter 12 Memories of Menlo Park From the spring of 1876 to 1886 Edison lived and did his work at Menlo Park and at this stage of the narrative midway in that interesting and eventful period it is appropriate to offer a few notes and jottings on the place itself around which tradition is already weaving its fancies just as at the time the outpouring of new inventions from it invested the name with sudden prominence and with the glamour of romance in 1876 I moved says Edison to Menlo Park, New Jersey on the Pennsylvania Railroad several miles below Elizabeth the move was due to trouble I had about rent I had rented a small shop in Newark on the top floor of a padlock factory by the month I gave notice that I would give it up at the end of the month paid the rent moved out and delivered the keys shortly afterward I was served with a paper probably a judgment wherein I was to pay nine months rent there was some law it seems that made a monthly renter liable for a year this seems so unjust that I determined to get out of a place that permitted such injustice for several Sundays he walked through different parts of New Jersey with two of his assistants before he decided on Menlo Park the change was a fortunate one for the inventor had married Miss Mary E. Stilwell and was now able to establish himself comfortably with his wife and family while enjoying immediate access to the new laboratory every moment thus saved was valuable today the place and region have gone back to the insignificance from which Edison's genius lifted them so startlingly a glance from the car windows reveals only a gently rolling landscape dotted with modest residences and unpretentious barns and there is nothing in sight by way of memorial to suggest that for nearly a decade this spot was the scene of the most concentrated and fruitful inventive activity the world has ever known close to the Menlo Park railway station is a group of gaunt and deserted buildings shelter of the casual tramp and slowly crumbling away when not destroyed by the carelessness of some ragged smoker this silent group of buildings comprises the famous old laboratory and workshops of Mr. Edison historic as being the birthplace of the carbon transmitter the phonograph the incandescent lamp and the spot where Edison also worked out his systems of electrical distribution his commercial dynamo his electric railway his megaphone his toss a mirror and many other inventions of greater or lesser degree here he continued moreover his earlier work on the quadruplex six top plaques multiplex and automatic telegraphs and did his notable pioneer work in wireless telegraphy as the reader knows it had been a master passion with Edison from boyhood up to possess a laboratory in which with free use of his own time and powers and with command of abundant material resources he could wrestle with nature and probe her closest secrets thus from the little seller at Port Hurham from the scant shelves in a baggage car from the nooks and corners of dingy telegraph offices and the grimy little shops in New York and Newark he had now come to the proud ownership of an establishment to which his favorite word laboratory might justly be applied here he could experiment to his heart's content and invent on a larger boulder scale than ever and he did mental park was the nearest hamlet omitting the laboratory structures it had only about seven houses the best looking of which Edison lived in a place that had a windmill pumping water into a reservoir one of the stories of the day was that Edison had his front gate so connected with the pumping plant that every visitor as he opened or closed the gate added involuntarily to the supply in the reservoir two or three of the houses were occupied by the families of members of the staff in the others borders were taken the laboratory of course furnishing all the patrons near the railway station was a small saloon kept by an old scotchman named Davis where billiards were played in idle moments and where in the long winter evenings the hot stove was a center of attraction to loungers and storytellers the truth is that there was very little social life of any kind possible under the strenuous conditions prevailing at the laboratory where if anywhere relaxation was enjoyed at odd intervals of fatigue and waiting the main laboratory was a spacious wooden building of two floors the office was in this building at first until removed to the brick library when that was finished there s l griffin an old telegraph friend of Edison acted as his secretary and had charge of a voluminous and amazing correspondence the office employees were the carmen brothers and the late John F. Randolph afterwards secretary according to mr. Francis gel of budapest then one of the staff to whom the writers were indebted for a great deal of valuable data on this period quote it was on the upper story of this laboratory that the most important experiments were executed and where the incandescent lamp was born this floor consisted of a large hall containing several long tables upon which could be found all the various instruments scientific and chemical apparatus that the arts at that time could produce books lay promiscuously about while here and there long lines of bicromate of potash cells could be seen together with experimental models of ideas that Edison or his assistants were engaged upon the sidewalls of this hall were lined with shelves filled with bottles files and other receptacles containing every imaginable chemical and other material that could be obtained while at the end of this hall and near the organ which stood in the rear was a large glass case containing the world's most precious metals in sheet and wire form together with very rare and costly chemicals when evening came on and the last rays of the setting sun penetrated through the side windows this hall looked like a veritable Faust laboratory on the ground floor we had our testing table which stood on two large pillars of brick built deep into the earth in order to get rid of all vibrations on account of the sensitive instruments that were upon it there was the Thompson reflecting mirror galvanometer and the electro meter while nearby were the standard cells by which the galvanometers were adjusted and standardized this testing table was connected by means of wires with all parts of the laboratory and machine shop so that measurements could be conveniently made from a distance as in those days we had no portable and direct reading instruments such as now exist opposite this table we installed later on our photometrical chamber which was constructed on the Bunsen principle a little way from this table and separated by a partition we had the chemical laboratory with its furnaces and stink chambers later on another chemical laboratory was installed near the photometer room and this doctor a haid had charged off next to the laboratory in importance was the machine shop a large and well-lighted building of brick at one end of which there was the boiler and engine room this shop contained light and heavy lays boring and drilling machines all kinds of planing machines in fact tools of all descriptions so that any apparatus however delicate or heavy could be made and built as might be required by Edison in experimenting mr. John Krusey had charge of this shop and was assisted by a number of skilled mechanics notably John Ott whose deft fingers and quick intuitive grasp of the master's ideas are still in demand under the more recent conditions at the Llewellyn Park laboratory in orange between the machine shop and the laboratory was a small building of wood used as a carpenter shop where Tom Logan plied his art nearby was the gasoline plant before the incandescent lamp was perfected the only illumination was from gasoline gas and that was used later for incandescent lamp glass blowing which was done in another small building on one side of the library apparently little or no lighting service was obtained from the Wallace farmer art lamps secured from Ansonia Connecticut the dynamo was probably needed for Edison's own experiments on the outskirts of the property was a small building in which lamp black was crudely but carefully manufactured and pressed into very small cakes for use in the Edison carbon transmitters of that time the night watchman Alfred Swanson took care of this curious plant which consisted of a battery of petroleum lamps that were forced to burn to the sooting point during his rounds in the night Swanson would find time to collect from the chimneys the soot that the lamps gave it was then weighed out into very small portions which were pressed into cakes or buttons by means of a hand press these little cakes were delicately packed away between layers of cotton in small light boxes and shipped to Bergman in New York by whom the telephone transmitters were being made a little later the Edison electric railway was built on the confines of the property out through the woods at first only a third of a mile in length but reaching ultimately to Pumptown almost three miles away Mr. Edison's own words may be quoted as to the man with whom he surrounded himself here and upon whose services he depended primarily for help in the accomplishment of his aims in an autobiographical article in the electrical world of March 5 1904 he says quote it is interesting to note that in addition to those mentioned above Charles Batchelor and Frank Upton I had around me other men who ever since have remained active in the field such as Mr. Francis Jell William J. Hammer Martin Force Ludwig K. Bohm not forgetting that good friend and co-worker the late John Krusey they found plenty to do in the various developments of the art and as I now look back I sometimes wonder how we did so much in so short a time unquote Mr. Jail in his reminiscences adds another name to the above namely that of John W. Lawson and then goes on to say quote these are the names of the pioneers of incandescent lighting who were continuously at the side of Edison day and night for some years and who under his guidance worked upon the carbon filament lamp from its birth to ripe maturity these men all had complete faith in his ability and stood by him as on a rock guarding their work with the secretiveness of a burglar-proof safe whenever it leaked out in the world that Edison was succeeding in his work on the electric light spies and others came to the park so it was of the utmost importance that the experiments and their results should be kept a secret until Edison had secured the protection of the patent office unquote with this staff was associated from the first Mr. E. H. Johnson whose work with Mr. Edison lay chiefly however outside the laboratory taking him to all parts of the country and to Europe there were also to be regarded as a detached members of it the Bergman Brothers manufacturing for Mr. Edison in New York and incessantly experimenting for him in addition there must be included Mr. Samuel Insel whose activities for many years as private secretary and financial manager were devoted solely to Mr. Edison's interest with Menwell Park as a center and main source of anxiety as to payrolls and other constantly recurring obligations the names of yet other associates occur from time to time in this narrative Edison men who have been very proud of their close relationship to the inventor and his work at old Menwell quote there was also Mr. Charles L. Clark who devoted himself mainly to engineering matters and later on acted as chief engineer of the Edison Electric Light Company for some years then there were William Holzer and James Hipple both of whom took an active part in the practical development of the glass blowing department of the laboratory and subsequently at the first Edison lamp factory at Menwell Park later on Mr. Jail Hipple and force assisted Mr. Bachelor to install the lamp works of the French Edison Company at Ivory Sursane then there were Mr. Charles T. Hughes Samuel de Mott and Charles T. Mott who devoted their time chiefly to commercial affairs Mr. Hughes conducted most of this work and later on took a prominent part in Edison's electric railway experiments his business ability was on a high level while his personal character endeared him to us all unquote among other now well-known men who came to us and assisted in various kinds of work where Mr. Atchison, Worth, Crosby, Herrick, and Hill while Dr. Hayd was placed by Mr. Edison in charge of a special chemical laboratory Dr. E. L. Nichols was also with us for a short time conducting a special series of experiments there was also Mr. Isaacs who did a great deal of photographic work and to whom we must be thankful for the pictures of Menwell Park in connection with Edison's work quote among others who were added to Mr. Crucey's staff in the machine shop where Mr. J. H. Vail and W. S. Andrews Mr. Vail had charge of the dynamo room he had a good general knowledge of machinery and very soon acquired such familiarity with the dynamos that he could skip about among them with astonishing agility to regulate their brushes or to throw rosin on the belts when they began to squeal later on he took an active part in the affairs and installations of the Edison light company Mr. Andrews stayed on Mr. Crucey's staff as long as the laboratory machine shop was kept open after which he went into the employee of the Edison electric light company and became actively engaged in the commercial and technical exploitation of the system another man who was with us at Menwell Park was Mr. Herman Claudius an Austrian who at one time was employed in connection with the state telegraphs of his country to him Mr. Edison assigned the task of making a complete model of the network of conductors for the contemplated first station in New York unquote Mr. Francis R. Upton who was early employed by Mr. Edison as his mathematician furnishes a pleasant vivid picture of his chief associates engaged on the memorable work at Menwell Park he says quote Mr. Charles Bachelor was Mr. Edison's principal assistant at that time he was an Englishman and came to this country to set up the thread weaving machinery for the Clark threadworks he was a most intelligent patient competent and loyal assistant to Mr. Edison I remember distinctly seeing him work many hours to mount a small filament and his hand would be as steady and his patience as unyielding at the end of those many hours as it was at the beginning in spite of repeated failures he was a wonderful mechanic the control that he had of his fingers was marvelous and his eyesight was sharp Mr. Batchelor's judgment and good sense were always in evidence Mr. Crucey was the superintendent a Swiss trained in the best Swiss ideas of accuracy he was a splendid mechanic with a vigorous temper and wonderful ability to work continuously and to get work out of men it was an ideal combination but of Edison Batchelor and Crucey Mr. Edison with his wonderful flow of ideas which were sharply defined in his mind as can be seen by any of the sketches that he made as he evidently always thinks in three dimensions Mr. Crucey willing to take the ideas and capable of comprehending them would distribute the work so as to get it done with marvelous quickness and great accuracy Mr. Batchelor was always ready for any special fine experimenting or observation and could hold to whatever he was at as long as Mr. Edison wished and always brought to bear on what he was at the greatest skill while Edison depended upon Upton for his mathematical work he was wont to check it up in a very practical manner as evidenced by the following incident described by Mr. Jail quote I was once with Mr. Upton calculating some tables which he had put me on when Mr. Edison appeared with a glass bulb having a pear shaped appearance in his hand it was the kind that we were going to use for our lamp experiments and Mr. Edison asked Mr. Upton to please calculate for him its cubic contents in centimeters now Mr. Upton was a very able mathematician who after he finished his studies at Princeton went to Germany and got his final gloss under that great master Hem Holtz whatever he did and worked on was executed in a pure mathematical manner and any wrangler at Oxford would have been delighted to see him juggle with integral and differential equations with a dexterity that was surprising he drew the shape of the bulb exactly on paper and got the equation of its lines with which he was going to calculate its contents when Mr. Edison again appeared and asked him what it was he showed Edison the work he had already done on the subject and told him that he would very soon finish calculating it why he said as an I would simply take that bulb and fill it with mercury and weigh it and from the weight of the mercury and its specific gravity I'll get it in five minutes and use less mental energy than is necessary in such a fatiguing operation mental park became ultimately the center of Edison's business life as it was of his inventing after the short distasteful period during the introduction of his lighting system when he spent a large part of his time at the offices at 65 Fifth Avenue New York or on the actual work connected with the New York Edison installation he settled back again in Menlo Park altogether Mr. Samuel Insole describes the business methods which prevailed throughout the earlier Menlo Park days of storm and stress and the curious conditions with which he had to deal as private secretary I never attempted to systematize Edison's business life Edison's whole method of work would upset the system of any office he was just as likely to be at work in his laboratory at midnight as midday he cared not for the hours of the day or the days of the week if he was exhausted he might more likely be asleep in the middle of the day than in the middle of the night as most of his work in the way of inventions was done at night I used to run his office on his close business methods as my experience admitted and I would get at him whenever it suited his convenience sometimes he would not go over his mail for days at a time but other times he would go regularly to his office in the morning at other times my engagements used to be with him to go over his business affairs at Menlo Park at night if I was occupied in New York during the day in fact as a matter of convenience I used more often to get at him at night as it left my days free to transact his affairs and enabled me probably at a midnight luncheon to get a few minutes of his time to look over his correspondence and get his directions as to what I should do in some particular negotiation or matter of finance while it was a matter of suiting Edison's convenience as to when I should transact business with him it also suited my own ideas as it enabled me after getting through my business with him to enjoy the privilege of watching him at his work and to learn something about the technical side of matters whatever knowledge I may have of the electric light and power industry I feel I owe it to the tuition of Edison he was about the most willing tutor and I must confess that he had to be a patient one here again occurs the reference to the incessant night work at Menlo Park a note that is struck in every reminiscence and in every record of the time but it is not to be inferred that the atmosphere of grim determination and persistent pursuit of the new invention characteristic of this period made life a burden to the small family of laborers associated with Edison many a time during the long weary nights of experimenting Edison would call a halt for refreshments which he had ordered always to be sent in when night work was in progress everything would be dropped all present would join in the meal and the last good story or joke would pass around in his notes mr. gel says our lunch always ended with a cigar and I may mention here that although Edison was never fastidious in eating he always relished a good cigar and seemed to find in it consolation and solace it often happened that while we were enjoying the cigars after our midnight repast one of the boys would start up a tune on the organ and we would all sing together or one of the others would give a solo another of the boys had a voice that sounded like something between the ring of an old tomato can and a pewter jug he had one song that he would sing while we roared with laughter he was also great in imitating the tin foil phonograph when bomb was in good humor he would play his zither now and then and amuse us by singing pretty german songs on many of these occasions the laboratory was the rendezvous of jolly and convivial visitors mostly old friends and acquaintances of mr. Edison some of the office employees would also drop in once in a while and as everybody present was always welcome to partake of the midnight meal we all enjoyed these gatherings after a while when we were ready to resume work our visitors would animate that they were going home to bed but we fellows could stay up and work and they would depart generally singing some song like good night ladies it often happened that when Edison had been working up to three or four o'clock in the morning he would lie down on one of the laboratory tables and with nothing but a couple of books for a pillow he would fall into a sound sleep he said it did him more good than being in a soft bed which spoils a man some of the laboratory assistants could be seen now and then sleeping on a table in the early morning hours if they're snoring became objectionable to those still at work the calmer was applied this machine consisted of a babbit soapbox without a cover a punnet was mounted a broad ratchet wheel with a crank while into the teeth of the wheel there played a stout elastic slab of wood the box would be placed on the table where the snorer was sleeping and the crank turned rapidly the racket thus produced was something terrible and the sleeper would jump up as though a typhoon had struck the laboratory the irrepressible spirit of humor in the old days although somewhat strenuous at times caused many a moment of hilarity which seemed to refresh the boys and enable them to work with renewed vigor after its manifestation mr. Upton remarks that often during the period of the invention of the incandescent lamp when under great strain and fatigue Edison would go to the organ and play tunes in a primitive way and come back to crack jokes with the staff but i have often felt that mr. Edison never could comprehend the limitations of the strength of other men as his own physical and mental strength have always seemed to be without limit he could work continuously as long as he wished and had sleep at his command his sleep was always instant profound and restful he has told me that he never dreamed i have known mr. Edison now for 31 years and feel that he has always kept his mind direct and simple going straight to the root of troubles one of the peculiar erities i have noticed is that i have never known him to break into a conversation going on round him and ask what people were talking about the nearest he would ever come to it was when there had evidently been some story told and his face would express a desire to join in the laugh which would immediately invite telling the story to him next to those who worked with Edison at the laboratory and were with him constantly at mental park were the visitors some of whom were his business associates some of them scientific men and some of them hero worshipers and curiosity hunters foremost in the first category was mr. E. H. Johnson who was in reality Edison's most intimate friend and was required for constant consultation but whose intense activity remarkable grasp of electrical principles and unusual powers of exposition led to his frequent detachment for long trips including those which resulted in the introduction of the telephone phonograph and electric light in england and on the continent a less frequent visitor was mr. S. Bergman who had all he needed to occupy his time in experimenting and manufacturing and whose contemporaneous Worcester street letterheads advertised Edison's inventions as being made there among the scientists were professor george f barker of philadelphia a big good natured philosopher whose valuable advice Edison esteemed highly in sharp contrast to him was the earnest serious roland of johns hopkins university afterward the leading american physicist of his day professor cf bracket and cf young of princeton university were often received always interested in what Edison was doing and proud that one of their own students mr. Upton was taking such a prominent part in the development of the work soon after the success of the lighting experiments and the installation at menlo part became known Edison was besieged by persons from all parts of the world anxious to secure rights and concessions for their respective countries among these was mr. louis raw of paris who organized the french Edison company the pioneer Edison lighting corporation in europe and who with the aid of mr. bachelor established lampworks and a machine shop at ivory sursane near paris in 1882 it was there that mr. necola tesla made his entree into the field of light and power and began his own career as an inventor and there also mr. etnie fordore general manager of the hungarian general electric company at budapest received his early training it was he who erected at athens the first european Edison station on the now universal three-wire system another visitor from europe a little later was mr. amal raffinow the present director of the great electricity gets cell shaft of germany he secured the rights for the empire and organized the berlin Edison system now one of the largest in the world through his extraordinary energy and enterprise the business made enormous strides and mr. raffinow has become one of the most conspicuous industrial figures in his native country from italy came professor colombo later a cabinet minister with his friend senior bootsy of milan the rights were secured for the peninsula colombo and his friends organized the italian Edison company and directed at milan the first central station in that country mr. john w leave junior now a vice president of the new york Edison company was sent over by mr. Edison to steer the enterprise technically and spent 10 years in building it up with such brilliant success that he was later decorated as commander of the order of the crown of italy by king victor another young american enlisted into european service was mr e g acheson the inventor of carburendum who built a number of plants in italy and france before he returned home mr. leave has since become president of the american institute of electrical engineers and the association of Edison illuminating companies while dr. acheson has been president of the american electrochemical society switzerland sent mr. turretini beaterman and thury all distinguished engineers to negotiate for rights in the republic and so it went with regard to all the other countries of europe as well as those of south america it was a question of keeping such visitors away rather than of inviting them to take up the exploitation of the Edison system for what time was not spent in personal interviews was required for the masses of letters from every country under the sun all making inquiries offering suggestions proposing terms nor were the visitors merely those on business bent there were the lion hunters and celebrities of whom sarah Bernhardt may serve as a type one visit of note was that paid by lieutenant g w d along who had an earnest and protracted conversation with Edison over the arctic expedition he was undertaking with the aid of mr. james bennett of the new york herald the genet was being fitted out and Edison told along that he would make and present him with a small dynamo machine some incandescent lamps and an arc lamp while the little dynamo was being built all the men in the laboratory wrote their names on the paper installation that was wound upon the iron core of the armature as the genet had no steam engine on board that could be used for the purpose Edison designed the dynamo so that it could be worked by manpower and told lieutenant de long it would keep the boys warm up in the arctic when they generated current with it the ill-fated ship never returned from her voyage but went down in the icy waters of the north there to remain until some future cataclysm of nature ten thousand years hence shall reveal the ship and the first marine dynamo as curious relics of a remote civilization Edison also furnished along with a set of telephones provided with extensible circuits so that parties on the ice floes could go long distances from the ship and still keep in communication with her so far as the writers can ascertain this is the first example of field telephony another nautical experiment that he made at this time suggested probably by the requirements of the arctic expedition was a boy that was floated in new york harbor and which contained a small Edison dynamo and two or three incandescent lamps the dynamo was driven by the wave or tide motion through intermediate mechanism and thus the lamps were lit up from time to time serving as signals these were the prototypes of the lighted boys which have since become familiar as in the channel off sandy hook one notable afternoon was that on which the new york board of alderman took a special train out to menlo park to see the lighting system with its conductor's underground in operation the Edison electric illuminating company was applying for a franchise and the alderman for lack of scientific training and specific practical information were very skeptical on the subject as indeed they might well be mr. Edison demonstrated personally the details and merits of the system to them the voltage was increased to a higher pressure than usual and all the incandescent lamps at menlo park did their best to win the approbation of the new york city fathers after Edison had finished exhibiting all the good points of his system he conducted his gas upstairs in the laboratory where a long table was spread with the best things that one of the most prominent new york caterers could furnish the laboratory witnessed high times that night for all were in the best of humor and many a bottle was drained in toasting the health of Edison and the alderman this was one of the extremely rare occasions on which Edison has addressed an audience but the state was worth the effort the representatives of new york could with justice drink the health of the young inventor whose system is one of the greatest boons the city has ever had conferred upon it among other frequent visitors was mr. Edison's father one of those amiable patriarchal characters with a Horace Greeley beard typical americans of the old school who would sometimes come into the laboratory with his two grandchildren a little boy and girl called dash and dot he preferred to sit and watch his brilliant son at work with an expression of satisfaction on his face that indicated a sense of happiness and content that his boy born in that distant humble home in Ohio had risen to fame and brought such honor upon the name it was indeed a pathetic sight to see a father venerate his son as the elder Edison did not less at home was mr. McKenzie the mount cleman's station agent the life of whose child Edison had saved when a trained news boy the old scotchman was one of the innocent chartered libertines of the place with an unlimited stock of good jokes and stories but seldom of any practical use on one occasion however when everything possible and impossible under the sun was being carbonized for lamp filaments he allowed a handful of his bushy red beard to be taken for the purpose and his laugh was the loudest when the Edison McKenzie hair lamps were brought up to incandescence their richness in red rays being slightly attributed to the nature of the filamentary material oddly enough a few years later some inventor actually took out a patent for making incandescent lamps with carbonized hair for filaments yet other visitors again haunted the place and with the following reminiscence of one of them from mr. Edison himself this part of the chapter must close quote at mental park one cold winter night there came into the laboratory a strange man in a most pitiful condition he was nearly frozen and he asked if he might sit by the stove in a few moments he asked for the head man and i was brought forward he had a head of abnormal size with highly intellectual features and a very small and emaciated body he said he was suffering very much and asked if i had any morphine as i had about everything in chemistry that could be bought i told him i had he requested that i give him some so i got the morphine sulfate he poured out enough to kill two men when i told him that we didn't keep a hotel for suicides and he had better cut the quantity down he then buried his legs and arms and they were literally pitted with scars due to the use of hypodermic syringes he said he had taken it for years and it required a big dose to have any effect i let him go ahead in a short while he seemed like another man and began to tell stories and there were about 50 of us who sat around listening until morning he was a man of great intelligence and education he said he was a Jew but there was no distinctive feature to verify this assertion he continued to stay around until he finished every combination of morphine with an acid that i had probably 10 ounces all told then he asked if he could have strict nine i had an ounce of the sulfate he took enough to kill a horse and asserted it had as good an effect as morphine when this was gone the only thing i had left was a chunk of crude opium perhaps two or three pounds he chewed this up and disappeared i was greatly disappointed because i would have laid in another stock of morphine to keep him at the laboratory about a week afterward he was found dead in a barn at Perth Amboy unquote returning to the work itself note of which has already been made in this and preceding chapters we find an interesting and unique reminiscence in mr jell's notes of the reversion to carbon as a filament in the lamps following an exhibition of metallic filament lamps given in the spring of 1879 to the men in the syndicate advancing the funds for these experiments they came to menlo park on a late afternoon train from new york it was already dark when they were conducted into the machine shop where we had several platinum lamps installed in series when Edison had finished explaining the principles and details of the lamp he asked cruci to let the dynamo machine run it was of the grammy type as our first dynamo of the Edison design was not yet finished Edison then ordered the juice to be turned on slowly today i can see those lamps rising to a cherry red like glow bugs and here mr Edison saying a little more juice and the lamps began to glow a little more is the command again and then one of the lamps he met for an instant a light like a star in the distance after which there is an eruption and a puff and the machine shop is in total darkness we knew instantly which lamp had failed and bachelor replaced that by a good one having a few and reserved nearby the operation was repeated two or three times with about the same results after which the party went into the library until it was time to catch the train for new york such an exhibition was decidedly discouraging and it was not a jubilant party that returned to new york but that night Edison remained in the laboratory meditating upon the results that the platinum lamp had given so far i was engaged reading a book near a table in the front while Edison was seated in a chair by a table near the organ with his head turned downward and that conspicuous lock of hair hanging loosely on one side he looked like napoleon in the celebrated picture on the eve of a great battle those days were heroic ones for he then battled against mighty odds and the prospects were dim and not very encouraging in cases of emergency Edison always possessed a keen faculty of deciding immediately and correctly what to do and the decision he then arrived at was predestined to be the turning point that led him on to ultimate success after that exhibition we had a house cleaning at the laboratory and the metallic filament lamps were stored away while preparations were made for our experiments on carbon lamps thus the work went on menlo park has hitherto been associated in the public thought with the telephone phonograph and incandescent lamp but it was there equally that the Edison dynamo and system of distribution were created and applied to their specific purposes while all this study of a possible lamp was going on mr. Upton was busy calculating the economy of the multiple arc system and making a great many tables to determine what resistance a lamp should have for the best results and at what point the proposed general system would fall off in the economy when the lamps were of the lower resistance that was then generally assumed to be necessary the world at that time had not the shadow of an idea as to what the principles of a multiple arc system should be enabling millions of lamps to be lighted off distributing circuits each lamp independent of every other but at menlo park at that remote period in the 70s mr. Edison's mathematician was formulating the inventor's conception in clear instructive figures and the work then executed has held its own ever since from the beginning of his experiments on electric light mr. Edison had a well-defined idea of producing not only a practicable lamp but also a system of commercial electric lighting such a scheme involved the creation of an entirely new art for there was nothing on the face of the earth from which to draw assistance or precedent unless we accept the elementary forms of dynamo's then in existence it is true there were several types of machines in use for the then very limited field of arc lighting but they were regarded as valueless as a part of a great comprehensive scheme which could supply everybody with light such machines were confessedly inefficient although representing the farthest reach of a young art a commission appointed at that time by the Franklin Institute and including professor Elihu Thompson investigated the merits of existing dynamo's and reported as to the best of them the grandma machine is the most economical as a means of converting motive force into electricity it utilizes in the arc from 38 to 41 percent of the motive work produced after deduction is made for friction and the resistance of the air they reported also that the brush art lighting machine produces in the luminous arc useful work equivalent to 31 percent of the motive power employed or to 38 and a half percent after the friction has been deducted commercial possibilities could not exist in the face of such low economy as this and mr. Edison realized that he would have to improve the dynamo himself if he wanted a better machine the scientific world at that time was engaged in a controversy regarding the external and internal resistance of a circuit in which a generator was situated discussing the subject mr. gel in his biographical notes says while this controversy raged in the scientific papers and criticism and confusion seemed at its height Edison and Upton discussed this question very thoroughly and Edison declared he did not intend to build up a system of distribution in which the external resistance would be equal to the internal resistance he said he was just about going to do the opposite he wanted a large external resistance and a low internal one he said he wanted to sell the energy outside of the station and not wasted in the dynamo and conductors where it brought no profits in these later days when these ideas of Edison are used as common property and are applied in every modern system of distribution it is astonishing to remember that when they were propounded they met with most vehement antagonism from the world at large Edison familiar with batteries in telegraphy could not bring himself to believe that any substitute generator of electrical energy could be efficient that used up half its own possible output before doing an equal amount of outside work undaunted by the dicta of contemporaneous science mr. Edison attacked the dynamo problem with his custom vigor and thoroughness he chose the drum form for his armature and experimented with different kinds of iron cores were made of cast iron others of forged iron and still others of sheets of iron of various thicknesses separated from each other by paper or paint these cores were then allowed to run in an excited field and after a given time their temperature was measured and noted by such practical methods Edison found that the thin laminated cores of sheet iron gave the least heat and had the least amount of wasteful eddy currents his experiments and ideas on magnetism at that period were far in advance of the time his work and tests regarding magnetism were repeated later on by hopkinson and cap who then elucidated the whole theory mathematically by means of formula and constants before this however Edison had attained these results by pioneer work founded on his original reasoning and utilize them in the construction of his dynamo thus revolutionizing the art of building such machines after thorough investigation of the magnetic qualities of different kinds of iron Edison began to make a study of winding the cores first determining the electromotive force generated per turn of wire at various speeds in fields of different intensities he also considered various forms and shapes for the armature and by methodical and systematic research obtained the data and best conditions upon which he could build his generator in the field magnets of his dynamo he constructed the cores and yolk of forged iron having a very large cross section which was a new thing in those days great attention was also paid to all the joints which were smoothed down so as to make a perfect magnetic contact the Edison dynamo with its large masses of iron was a vivid contrast to the then existing types with their meager quantities of the ferric element Edison also made tests on his field magnets by slowly raising the strength of the exciting current so that he obtained figures similar to those shown by a magnetic curve and in this way found where saturation commenced and where it was useless to expend more current on the field if he had asked Upton at the time to formulate the results of his work in this direction for publication he would have anticipated the historic work on magnetism that was executed by the two other investigators hopkinson and cap later on the laboratory notebooks of the period bear abundant evidence of the systematic and searching nature of these experiments and investigations in the hundreds of pages of notes sketches calculations and tables made at the time by Edison Upton bachelor jail and by others who from time to time were entrusted with special experiments to elucidate some particular point Mr. Jell says the experiments on armature winding were also very interesting Edison had a number of small wooden cores made at both ends of which we inserted little brass nails and we wound the wooden cores with twine as if it were wire on an armature in this way we studied armature winding and had matches where each of us had a core while bets were made as to who would be the first to finish properly and correctly a certain kind of winding care had to be taken that the wound core corresponded to the direction of the current supposing it were placed in a field and revolved after Edison had decided this question Upton made drawings and tables from which the real armatures were wound and connected to the commutator to a student of today all this seems simple but in those days the art of constructing dynamos was about as dark as air navigation is at present Edison also improved the armature by dividing it and the commutator into a far greater number of sections than up to that time had been the practice he was also the first to use mica in insulating the commutator sections from each other in the meantime during the progress of the investigations on the dynamo word had gone out to the world that Edison expected to invent a generator of greater efficiency than any that existed at the time again he was assailed and ridiculed by the technical press for had not the foremost electricians and physicists of Europe and America worked for years on the production of dynamos and art lamps as they then existed even though this young man at Menlo Park had done some wonderful things for telegraphy and telephony even if he had recorded and reproduced human speech he had his limitations and could not upset the settled dictum of science that the internal resistance must equal the external resistance such was the trend of public opinion at the time but after Mr. Crucey had finished the first practical dynamo and after Mr. Upton had tested it thoroughly and verified his figures and results several times before he also was surprised Edison was able to tell the world that he had made a generator giving an efficiency of 90 percent 90 percent as against 40 percent was a mighty hit and the world would not believe it criticism an argument were again at their height while Upton as Edison's dualist was kept busy replying to private and public challenges of the fact the tremendous progress of the world in the last quarter of a century owing to the revolution caused by the all conquering march of heavy current engineering is the outcome of Edison's work at Menlo Park that raised the efficiency of the dynamo from 40 percent to 90 percent Mr. Upton sums it all up very precisely in his remarks upon this period quote what has now been made clear by accurate nomenclature was then very foggy in the textbooks Mr. Edison had completely grasped the effect of subdivision of circuits and the influence of wires leading to such subdivisions when it was most difficult to express what he knew in technical language I remember distinctly when Mr. Edison gave me the problem of placing a motor in circuit in multiple art with a fixed resistance and I had to work out the problem entirely as I could find no prior solution there was nothing I could find bearing upon the counter-electromotive force of the armature and the effect of the resistance of the armature on the work given out by the armature it was a wonderful experience to have problems given me out of the intuitions of a great mind based on enormous experience in practical work and applying to new lines of progress one of the main impressions left upon me after knowing Mr. Edison for many years is the marvelous accuracy of his guesses he will see the general nature of a result long before it can be reached by mathematical calculation his greatness was always to be clearly seen when difficulties arose they always made him cheerful and started him thinking and very soon would come a line of suggestions which would not end until the difficulty was met and overcome or found insurmountable I have often felt that Mr. Edison got himself purposely into trouble by premature publications and otherwise so that he would have a full incentive to get himself out of trouble this chapter may well end with a statement from Mr. Jell shrewd and observant as a participator in all the early work of the development of the Edison lighting system quote those who were gathered around him in the old Menlo Park laboratory enjoyed his confidence and he theirs nor was this confidence ever abused he was respected with a respect which only great men can obtain and he never showed by any word or act that he was their employer in a sense that would hurt the feelings as is often the case in the ordinary course of business life he can burst argued and disputed with us all as if he were a colleague on the same footing it was his winning ways and manners that attached us all so loyally to his side and made us ever ready with a boundless devotion to execute any request or desire unquote thus does a great magnet run through a heap of sand and filings exert its lines of force and attract irresistibly to itself the iron and steel particles that are its affinity and having sifted them out leaving the useless dust behind hold them to itself with responsive tenacity end of chapter 12 recording by Ralph snelton springville utah