Here was the outline of the programme laid down in the autumn of 1878, and pursued through all its difficulties to definite accomplishment in about eighteen months, some of the steps being made immediately, others being taken as the art evolved. It is not to be imagined for one moment that Edison performed all the experiments with his own hands. The method of working at Menlo Park has already been described in these pages by those who participated. It would not only have been physically impossible for one man to have done all this work himself, in view of the time and labor required, and the endless detail; but most of the apparatus and devices invented or suggested by him as the art took shape required the handiwork of skilled mechanics and artisans of a high order of ability. Toward the end of 1879 the laboratory force thus numbered at least one hundred earnest men. In this respect of collaboration, Edison has always adopted a policy that must in part be taken to explain his many successes. Some inventors of the greatest ability, dealing with ideas and conceptions of importance, have found it impossible to organize or even to tolerate a staff of co-workers, preferring solitary and secret toil, incapable of team work, or jealous of any intrusion that could possibly bar them from a full and complete claim to the result when obtained. Edison always stood shoulder to shoulder with his associates, but no one ever questioned the leadership, nor was it ever in doubt where the inspiration originated. The real truth is that Edison has always been so ceaselessly fertile of ideas himself, he has had more than his whole staff could ever do to try them all out; he has sought co-operation, but no exterior suggestion. As a matter of fact a great many of the "Edison men" have made notable inventions of their own, with which their names are imperishably associated; but while they were with Edison it was with his work that they were and must be busied.

It was during this period of "inventing a system" that so much systematic and continuous work with good results was done by Edison in the design and perfection of dynamos. The value of his contributions to the art of lighting comprised in this work has never been fully understood or appreciated, having been so greatly overshadowed by his invention of the incandescent lamp, and of a complete system of distribution. It is a fact, however, that the principal improvements he made in dynamo-electric generators were of a radical nature and remain in the art. Thirty years bring about great changes, especially in a field so notably progressive as that of the generation of electricity; but different as are the dynamos of to-day from those of the earlier period, they embody essential principles and elements that Edison then marked out and elaborated as the conditions of success. There was indeed prompt appreciation in some well-informed quarters of what Edison was doing, evidenced by the sensation caused in the summer of 1881, when he designed, built, and shipped to Paris for the first Electrical Exposition ever held, the largest dynamo that had been built up to that time. It was capable of lighting twelve hundred incandescent lamps, and weighed with its engine twenty-seven tons, the armature alone weighing six tons. It was then, and for a long time after, the eighth wonder of the scientific world, and its arrival and installation in Paris were eagerly watched by the most famous physicists and electricians of Europe.

Edison's amusing description of his experience in shipping the dynamo to Paris when built may appropriately be given here: "I built a very large dynamo with the engine directly connected, which I intended for the Paris Exposition of 1881. It was one or two sizes larger than those I had previously built. I had only a very short period in which to get it ready and put it on a steamer to reach the Exposition in time. After the machine was completed we found the voltage was too low. I had to devise a way of raising the voltage without changing the machine, which I did by adding extra magnets. After this was done, we tested the machine, and the crank-shaft of the engine broke and flew clear across the shop. By working night and day a new crank-shaft was put in, and we only had three days left from that time to get it on board the steamer; and had also to run a test. So we made arrangements with the Tammany leader, and through him with the police, to clear the street--one of the New York crosstown streets--and line it with policemen, as we proposed to make a quick passage, and didn't know how much time it would take. About four hours before the steamer had to get it, the machine was shut down after the test, and a schedule was made out in advance of what each man had to do. Sixty men were put on top of the dynamo to get it ready, and each man had written orders as to what he was to perform. We got it all taken apart and put on trucks and started off. They drove the horses with a fire-bell in front of them to the French pier, the policemen lining the streets. Fifty men were ready to help the stevedores get it on the steamer--and we were one hour ahead of time."

This Exposition brings us, indeed, to a dramatic and rather pathetic parting of the ways. The hour had come for the old laboratory force that had done such brilliant and memorable work to disband, never again to assemble under like conditions for like effort, although its members all remained active in the field, and many have ever since been associated prominently with some department of electrical enterprise. The fact was they had done their work so well they must now disperse to show the world what it was, and assist in its industrial exploitation. In reality, they were too few for the demands that reached Edison from all parts of the world for the introduction of his system; and in the emergency the men nearest to him and most trusted were those upon whom he could best depend for such missionary work as was now required. The disciples full of fire and enthusiasm, as well as of knowledge and experience, were soon scattered to the four winds, and the rapidity with which the Edison system was everywhere successfully introduced is testimony to the good judgment with which their leader had originally selected them as his colleagues. No one can say exactly just how this process of disintegration began, but Mr. E. H. John- son had already been sent to England in the Edison interests, and now the question arose as to what should be done with the French demands and the Paris Electrical Exposition, whose importance as a point of new departure in electrical industry was speedily recognized on both sides of the Atlantic. It is very interesting to note that as the earlier staff broke up, Edison became the centre of another large body, equally devoted, but more particularly concerned with the commercial development of his ideas. Mr. E. G. Acheson mentions in his personal notes on work at the laboratory, that in December of 1880, while on some experimental work, he was called to the new lamp factory started recently at Menlo Park, and there found Edison, Johnson, Batchelor, and Upton in conference, and "Edison informed me that Mr. Batchelor, who was in charge of the construction, development, and operation of the lamp factory, was soon to sail for Europe to prepare for the exhibit to be made at the Electrical Exposition to be held in Paris during the coming summer." These preparations overlap the reinforcement of the staff with some notable additions, chief among them being Mr. Samuel Insull, whose interesting narrative of events fits admirably into the story at this stage, and gives a vivid idea of the intense activity and excitement with which the whole atmosphere around Edison was then surcharged: "I first met Edison on March 1, 1881. I arrived in New York on the City of Chester about five or six in the evening, and went direct to 65 Fifth Avenue. I had come over to act as Edison's private secretary, the position having been obtained for me through the good offices of Mr. E. H. Johnson, whom I had known in London, and who wrote to Mr. U. H. Painter, of Washington, about me in the fall of 1880. Mr. Painter sent the letter on to Mr. Batchelor, who turned it over to Edison. Johnson returned to America late in the fall of 1880, and in January, 1881, cabled to me to come to this country. At the time he cabled for me Edison was still at Menlo Park, but when I arrived in New York the famous offices of the Edison Electric Light Company had been opened at `65' Fifth Avenue, and Edison had moved into New York with the idea of assisting in the exploitation of the Light Company's business.