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 seemed 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. stillwell, 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.

to-day 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 tasimeter, and many other inventions of greater or lesser degree. here he continued, moreover, his earlier work on the quadruplex, sextuplex, 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 cellar at port huron, 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, bolder scale than ever—and he did!

menlo park was the merest 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 boarders 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 centre of attraction to loungers and story-tellers. 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 carman brothers and the late john f. randolph, afterwards secretary. according to mr. francis jehl, of budapest, then one of the staff, to whom the writers are indebted for a great deal of valuable data on this period: "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 bichromate-of-potash cells could be seen, together with experimental models of ideas that edison or his assistants were engaged upon. the side walls of this hall were lined with shelves filled with bottles, phials, 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 thomson reflecting mirror galvanometer and electrometer, 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 dr. a. haid had charge of."

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 lathes, 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 kruesi 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 laboratory. apparently little or no lighting service was obtained from the wallace-farmer arc 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 lampblack 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 bergmann 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 men with whom he surrounded himself here and upon whose services he depended principally for help in the accomplishment of his aims. in an autobiographical article in the electrical world of march 5, 1904, he says: "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 messrs. francis jehl, william j. hammer, martin force, ludwig k. boehm, not forgetting that good friend and co-worker, the late john kruesi. 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." mr. jehl in his reminiscences adds another name to the above—namely, that of john w. lawson, and then goes on to say: "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." 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 detached members of it the bergmann brothers, manufacturing for mr. edison in new york, and incessantly experimenting for him. in addition there must be included mr. samuel insull, whose activities for many years as private secretary and financial manager were devoted solely to mr. edison's interests, with menlo park as a centre and main source of anxiety as to pay-rolls 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 menlo. "there was also mr. charles l. clarke, 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 menlo park. later on messrs. jehl, hipple, and force assisted mr. batchelor to install the lamp-works of the french edison company at ivry-sur-seine. then there were messrs. charles t. hughes, samuel d. 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."

among other now well-known men who came to us and assisted in various kinds of work were messrs. acheson, worth, crosby, herrick, and hill, while doctor haid 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 menlo park in connection with edison's work.

"among others who were added to mr. kruesi's staff in the machine-shop were messrs. 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. kruesi's staff as long as the laboratory machine-shop was kept open, after which he went into the employ 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 menlo 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."

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 menlo park. he says: "mr. charles batchelor 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 thread-works. 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 marvellous, and his eyesight was sharp. mr. batchelor's judgment and good sense were always in evidence.

"mr. kruesi 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, that of edison, batchelor, and kruesi. 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. kruesi, willing to take the ideas, and capable of comprehending them, would distribute the work so as to get it done with marvellous 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. jehl: "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 centimetres. 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, helmholtz. 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,' said edison, '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.'"

menlo park became ultimately the centre 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 insull 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 as 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. jehl 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 boehm 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 intimate 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, 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 their snoring became objectionable to those still at work, the 'calmer' was applied. this machine consisted of a babbitt's soap box without a cover. upon it 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 enabled 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 thirty-one years, and feel that he has always kept his mind direct and simple, going straight to the root of troubles. one of the peculiarities i have noticed is that i have never known him to break into a conversation going on around 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 menlo park were the visitors, some of whom were his business associates, some of them scientific men, and some of them hero-worshippers 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. bergmann, who had all he needed to occupy his time in experimenting and manufacturing, and whose contemporaneous wooster street letter-heads advertised edison's inventions as being made there, among the scientists were prof. 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 rowland, of johns hopkins university, afterward the leading american physicist of his day. profs. c. f. brackett and c. f. 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 park 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 rau, of paris, who organized the french edison company, the pioneer edison lighting corporation in europe, and who, with the aid of mr. batchelor, established lamp-works and a machine-shop at ivry sur-seine, near paris, in 1882. it was there that mr. nikola tesla made his entree into the field of light and power, and began his own career as an inventor; and there also mr. etienne fodor, 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. emil rathenau, the present director of the great allgemeine elektricitaets gesellschaft 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. rathenau 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 signor buzzi, of milan. the rights were secured for the peninsula; colombo and his friends organized the italian edison company, and erected at milan the first central station in that country. mr. john w. lieb, jr., now a vice-president of the new york edison company, was sent over by mr. edison to steer the enterprise technically, and spent ten 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 carborundum, who built a number of plants in italy and france before he returned home. mr. lieb has since become president of the american institute of electrical engineers and the association of edison illuminating companies, while doctor acheson has been president of the american electrochemical society.

switzerland sent messrs. turrettini, biedermann, 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 lieut. g. w. de long, who had an earnest and protracted conversation with edison over the arctic expedition he was undertaking with the aid of mr. james gordon bennett, of the new york herald. the jeannette was being fitted out, and edison told de long 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 insulation that was wound upon the iron core of the armature. as the jeannette had no steam-engine on board that could be used for the purpose, edison designed the dynamo so that it could be worked by man power 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 de long 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 buoy 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 buoys which have since become familiar, as in the channel off sandy hook.

one notable afternoon was that on which the new york board of aldermen took a special train out to menlo park to see the lighting system with its conductors underground in operation. the edison electric illuminating company was applying for a franchise, and the aldermen, for lack of scientific training and specific practical information, were very sceptical 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 guests 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 aldermen." this was one of the extremely rare occasions on which edison has addressed an audience; but the stake 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. mackenzie, the mt. clemens station agent, the life of whose child edison had saved when a train newsboy. 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-mackenzie hair lamps were brought up to incandescence—their richness in red rays being slyly 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: "at menlo 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 sulphate. 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 bared 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 fifty 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 ten ounces all told. then he asked if he could have strychnine. i had an ounce of the sulphate. 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."

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. jehl'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 kruesi to let the dynamo machine run. it was of the gramme type, as our first dynamo of the edison design was not yet finished. edison then ordered the 'juice' to be turned on slowly. to-day i can see those lamps rising to a cherry red, like glowbugs, and hear 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 emits 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 batchelor replaced that by a good one, having a few in reserve near by. 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 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 seventies 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 except the elementary forms of dynamos 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 prof. elihu thomson, investigated the merits of existing dynamos and reported as to the best of them: "the gramme machine is the most economical as a means of converting motive force into electricity; it utilizes in the arc from 38 to 41 per cent. of the motive work produced, after deduction is made for friction and the resistance of the air." they reported also that the brush arc lighting machine "produces in the luminous arc useful work equivalent to 31 per cent. of the motive power employed, or to 38 1/2 per cent. 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. jehl, 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 waste it 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 accustomed 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 kapp, who then elucidated the whole theory mathematically by means of formulae and constants. before this, however, edison had attained these results by pioneer work, founded on his original reasoning, and utilized 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 yoke 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 meagre 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 kapp, later on.

the laboratory note-books 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, batchelor, jehl, and by others who from time to time were intrusted with special experiments to elucidate some particular point. mr. jehl 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 to-day 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 mean time, 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 arc 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. kruesi had finished the first practical dynamo, and after mr. upton had tested it thoroughly and verified his figures and results several times—for he also was surprised—edison was able to tell the world that he had made a generator giving an efficiency of 90 per cent." ninety per cent. as against 40 per cent. was a mighty hit, and the world would not believe it. criticism and argument were again at their height, while upton, as edison's duellist, 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 per cent. to 90 per cent."

mr. upton sums it all up very precisely in his remarks upon this period: "what has now been made clear by accurate nomenclature was then very foggy in the text-books. 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 arc 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 marvellous 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 the trouble."

this chapter may well end with a statement from mr. jehl, shrewd and observant, as a participator in all the early work of the development of the edison lighting system: "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 conversed, 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." 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.