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A NOTED inventor once said at the end of a lifetime of fighting to defend his rights, that he found there were three stages in all great inventions: the first, in which people said the thing could not be done; the second, in which they said anybody could do it; and the third, in which they said it had always been done by everybody. In his central- station work Edison has had very much this kind of experience; for while many of his opponents came to acknowledge the novelty and utility of his plans, and gave him unstinted praise, there are doubtless others who to this day profess to look upon him merely as an adapter. How different the view of so eminent a scientist as Lord Kelvin was, may be appreciated from his remark when in later years, in reply to the question why some one else did not invent so obvious and simple a thing as the Feeder System, he said: "The only answer I can think of is that no one else was Edison."
Undaunted by the attitude of doubt and the predictions of impossibility, Edison had pushed on until he was now able to realize all his ideas as to the establishment of a central station in the work that culminated in New York City in 1882. After he had conceived the broad plan, his ambition was to create the initial plant on Manhattan Island, where it would be convenient of access for watching its operation, and where the demonstration of its practicability would have influence in financial circles. The first intention was to cover a district extending from Canal Street on the north to Wall Street on the south; but Edison soon realized that this territory was too extensive for the initial experiment, and he decided finally upon the district included between Wall, Nassau, Spruce, and Ferry streets, Peck Slip and the East River, an area nearly a square mile in extent. One of the preliminary steps taken to enable him to figure on such a station and system was to have men go through this district on various days and note the number of gas jets burning at each hour up to two or three o'clock in the morning. The next step was to divide the region into a number of sub-districts and institute a house-to-house canvass to ascertain precisely the data and conditions pertinent to the project. When the canvass was over, Edison knew exactly how many gas jets there were in every building in the entire district, the average hours of burning, and the cost of light; also every consumer of power, and the quantity used; every hoistway to which an electric motor could be applied; and other details too numerous to mention, such as related to the gas itself, the satisfaction of the customers, and the limitations of day and night demand. All this information was embodied graphically in large maps of the district, by annotations in colored inks; and Edison thus could study the question with every detail before him. Such a reconnaissance, like that of a coming field of battle, was invaluable, and may help give a further idea of the man's inveterate care for the minutiae of things.
The laboratory note-books of this period--1878- 80, more particularly--show an immense amount of calculation by Edison and his chief mathematician, Mr. Upton, on conductors for the distribution of current over large areas, and then later in the district described. With the results of this canvass before them, the sizes of the main conductors to be laid throughout the streets of this entire territory were figured, block by block; and the results were then placed on the map. These data revealed the fact that the quantity of copper required for the main conductors would be exceedingly large and costly; and, if ever, Edison was somewhat dismayed. But as usual this apparently insurmountable difficulty only spurred him on to further effort. It was but a short time thereafter that he solved the knotty problem by an invention mentioned in a previous chapter. This is known as the "feeder and main" system, for which he signed the application for a patent on August 4, 1880. As this invention effected a saving of seven-eighths of the cost of the chief conductors in a straight multiple arc system, the mains for the first district were refigured, and enormous new maps were made, which became the final basis of actual installation, as they were subsequently enlarged by the addition of every proposed junction-box, bridge safety-catch box, and street-intersection box in the whole area.
When this patent, after protracted fighting, was sustained by Judge Green in 1893, the Electrical Engineer remarked that the General Electric Company "must certainly feel elated" because of its importance; and the journal expressed its fear that although the specifications and claims related only to the maintenance of uniform pressure of current on lighting circuits, the owners might naturally seek to apply it also to feeders used in the electric-railway work already so extensive. At this time, however, the patent had only about a year of life left, owing to the expiration of the corresponding English patent. The fact that thirteen years had elapsed gives a vivid idea of the ordeal involved in sustaining a patent and the injustice to the inventor, while there is obviously hardship to those who cannot tell from any decision of the court whether they are infringing or not. It is interesting to note that the preparation for hearing this case in New Jersey was accompanied by models to show the court exactly the method and its economy, as worked out in comparison with what is known as the "tree system" of circuits--the older alternative way of doing it. As a basis of comparison, a district of thirty-six city blocks in the form of a square was assumed. The power station was placed at the centre of the square; each block had sixteen consumers using fifteen lights each. Conductors were run from the station to supply each of the four quarters of the district with light. In one example the "feeder" system was used; in the other the "tree." With these models were shown two cubes which represented one one-hundredth of the actual quantity of copper required for each quarter of the district by the two-wire tree system as compared with the feeder system under like conditions. The total weight of copper for the four quarter districts by the tree system was 803,250 pounds, but when the feeder system was used it was only 128,739 pounds! This was a reduction from $23.24 per lamp for copper to $3.72 per lamp. Other models emphasized this extraordinary contrast. At the time Edison was doing this work on economizing in conductors, much of the criticism against him was based on the assumed extravagant use of copper implied in the obvious "tree" system, and it was very naturally said that there was not enough copper in the world to supply his demands. It is true that the modern electrical arts have been a great stimulator of copper production, now taking a quarter of all made; yet evidently but for such inventions as this such arts could not have come into existence at all, or else in growing up they would have forced copper to starvation prices.
 For description of feeder patent see Appendix.
It should be borne in mind that from the outset Edison had determined upon installing underground conductors as the only permanent and satisfactory method for the distribution of current from central stations in cities; and that at Menlo Park he laid out and operated such a system with about four hundred and twenty-five lamps. The underground system there was limited to the immediate vicinity of the laboratory and was somewhat crude, as well as much less complicated than would be the network of over eighty thousand lineal feet, which he calculated to be required for the underground circuits in the first district of New York City. At Menlo Park no effort was made for permanency; no provision was needed in regard to occasional openings of the street for various purposes; no new customers were to be connected from time to time to the mains, and no repairs were within contemplation. In New York the question of permanency was of paramount importance, and the other contingencies were sure to arise as well as conditions more easy to imagine than to forestall. These problems were all attacked in a resolute, thoroughgoing manner, and one by one solved by the invention of new and unprecedented devices that were adequate for the purposes of the time, and which are embodied in apparatus of slight modification in use up to the present day.
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Edison, His Life and Inventions -by- F. L. Dyer and T. C. Martin