Edison, His Life and Inventions Part 14

[Footnote 12: We quote the following interesting notes of Mr. Charles L. Clarke on the question of see-sawing, or "hunting," as it was afterward termed:

"In the Holborn Viaduct station the difficulty of 'hunting' was not experienced. At the time the 'Jumbos' were first operated in multiple arc, April 8, 1882, one machine was driven by a Porter-Allen engine, and the other by an Armington & Sims engine, and both machines were on a solid foundation. At the station at Milan, Italy, the first 'Jumbos'

operated in multiple arc were driven by Porter-Allen engines, and dash-pots were applied to the governors. These machines were also upon a solid foundation, and no trouble was experienced.

"At the Pearl Street station, however, the machines were supported upon long iron floor-beams, and at the high speed of 350 revolutions per minute, considerable vertical vibration was given to the engines. And the writer is inclined to the opinion that this vibration, acting in the same direction as the action of gravitation, which was one of the two controlling forces in the operation of the Porter-Allen governor, was the primary cause of the 'hunting.' In the Armington & Sims engine the controlling forces in the operation of the governor were the centrifugal force of revolving weights, and the opposing force of compressed springs, and neither the action of gravitation nor the vertical vibrations of the engine could have any sensible effect upon the governor."]

The Pearl Street station, as this first large plant was called, made rapid and continuous growth in its output of electric current. It started, as we have said, on September 4, 1882, supplying about four hundred lights to a comparatively small number of customers. Among those first supplied was the banking firm of Drexel, Morgan & Company, corner of Broad and Wall streets, at the outermost limits of the system. Before the end of December of the same year the light had so grown in favor that it was being supplied to over two hundred and forty customers whose buildings were wired for over five thousand lamps. By this time three more "Jumbos" had been added to the plant. The output from this time forward increased steadily up to the spring of 1884, when the demands of the station necessitated the installation of two additional "Jumbos"

in the adjoining building, which, with the venous improvements that had been made in the mean time, gave the station a capacity of over eleven thousand lamps actually in service at any one time.

During the first three months of operating the Pearl Street station light was supplied to customers without charge. Edison had perfect confidence in his meters, and also in the ultimate judgment of the public as to the superiority of the incandescent electric light as against other illuminants. He realized, however, that in the beginning of the operation of an entirely novel plant there was ample opportunity for unexpected contingencies, although the greatest care had been exercised to make everything as perfect as possible. Mechanical defects or other unforeseen troubles in any part of the plant or underground system might arise and cause temporary stoppages of operation, thus giving grounds for uncertainty which would create a feeling of public distrust in the permanence of the supply of light.

As to the kind of mishap that was wont to occur, Edison tells the following story: "One afternoon, after our Pearl Street station started, a policeman rushed in and told us to send an electrician at once up to the corner of Ann and Na.s.sau streets--some trouble. Another man and I went up. We found an immense crowd of men and boys there and in the adjoining streets--a perfect jam. There was a leak in one of our junction-boxes, and on account of the cellars extending under the street, the top soil had become insulated. Hence, by means of this leak powerful currents were pa.s.sing through this thin layer of moist earth.

When a horse went to pa.s.s over it he would get a very severe shock. When I arrived I saw coming along the street a ragman with a dilapidated old horse, and one of the boys told him to go over on the other side of the road--which was the place where the current leaked. When the ragman heard this he took that side at once. The moment the horse struck the electrified soil he stood straight up in the air, and then reared again; and the crowd yelled, the policeman yelled; and the horse started to run away. This continued until the crowd got so serious that the policeman had to clear it out; and we were notified to cut the current off. We got a gang of men, cut the current off for several junction-boxes, and fixed the leak. One man who had seen it came to me next day and wanted me to put in apparatus for him at a place where they sold horses. He said he could make a fortune with it, because he could get old nags in there and make them act like thoroughbreds."

So well had the work been planned and executed, however, that nothing happened to hinder the continuous working of the station and the supply of light to customers. Hence it was decided in December, 1882, to begin charging a price for the service, and, accordingly, Edison electrolytic meters were installed on the premises of each customer then connected.

The first bill for lighting, based upon the reading of one of these meters, amounted to $50.40, and was collected on January 18, 1883, from the Ansonia Bra.s.s and Copper Company, 17 and 19 Cliff Street. Generally speaking, customers found that their bills compared fairly with gas bills for corresponding months where the same amount of light was used, and they paid promptly and cheerfully, with emphatic encomiums of the new light. During November, 1883, a little over one year after the station was started, bills for lighting amounting to over $9000 were collected.

An interesting story of meter experience in the first few months of operation of the Pearl Street station is told by one of the "boys" who was then in position to know the facts; "Mr. J. P. Morgan, whose firm was one of the first customers, expressed to Mr. Edison some doubt as to the accuracy of the meter. The latter, firmly convinced of its correctness, suggested a strict test by having some cards printed and hung on each fixture at Mr. Morgan's place. On these cards was to be noted the number of lamps in the fixture, and the time they were turned on and off each day for a month. At the end of that time the lamp-hours were to be added together by one of the clerks and figured on a basis of a definite amount per lamp-hour, and compared with the bill that would be rendered by the station for the corresponding period. The results of the first month's test showed an apparent overcharge by the Edison company. Mr. Morgan was exultant, while Mr. Edison was still confident and suggested a continuation of the test. Another month's trial showed somewhat similar results. Mr. Edison was a little disturbed, but insisted that there was a mistake somewhere. He went down to Drexel, Morgan & Company's office to investigate, and, after looking around, asked when the office was cleaned out. He was told it was done at night by the janitor, who was sent for, and upon being interrogated as to what light he used, said that he turned on a central fixture containing about ten lights. It came out that he had made no record of the time these lights were in use. He was told to do so in future, and another month's test was made. On comparison with the company's bill, rendered on the meter-reading, the meter came within a few cents of the amount computed from the card records, and Mr. Morgan was completely satisfied of the accuracy of the meter."

It is a strange but not extraordinary commentary on the perversity of human nature and the lack of correct observation, to note that even after the Pearl Street station had been in actual operation twenty-four hours a day for nearly three months, there should still remain an att.i.tude of "can't be done." That such a scepticism still obtained is evidenced by the public prints of the period. Edison's electric-light system and his broad claims were freely discussed and animadverted upon at the very time he was demonstrating their successful application. To show some of the feeling at the time, we reproduce the following letter, which appeared November 29, 1882:

"To the Editor of the Sun:

"SIR,--In reading the discussions relative to the Pearl Street station of the Edison light, I have noted that while it is claimed that there is scarcely any loss from leakage of current, nothing is said about the loss due to the resistance of the long circuits. I am informed that this is the secret of the failure to produce with the power in position a sufficient amount of current to run all the lamps that have been put up, and that while six, and even seven, lights to the horse-power may be produced from an isolated plant, the resistance of the long underground wires reduces this result in the above case to less than three lights to the horse-power, thus making the cost of production greatly in excess of gas. Can the Edison company explain this? 'INVESTIGATOR'."

This was one of the many anonymous letters that had been written to the newspapers on the subject, and the following reply by the Edison company was printed December 3, 1882:

"To the Editor of the Sun:

"SIR,--'Investigator' in Wednesday's Sun, says that the Edison company is troubled at its Pearl Street station with a 'loss of current, due to the resistance of the long circuits'; also that, whereas Edison gets 'six or even seven lights to the horse-power in isolated plants, the resistance of the long underground wires reduces that result in the Pearl Street station to less than three lights to the horse-power.' Both of these statements are false. As regards loss due to resistance, there is a well-known law for determining it, based on Ohm's law. By use of that law we knew in advance, that is to say, when the original plans for the station were drawn, just what this loss would be, precisely the same as a mechanical engineer when constructing a mill with long lines of shafting can forecast the loss of power due to friction. The practical result in the Pearl Street station has fully demonstrated the correctness of our estimate thus made in advance. As regards our getting only three lights per horse-power, our station has now been running three months, without stopping a moment, day or night, and we invariably get over six lamps per horse-power, or substantially the same as we do in our isolated plants. We are now lighting one hundred and ninety-three buildings, wired for forty-four hundred lamps, of which about two-thirds are in constant use, and we are adding additional houses and lamps daily. These figures can be verified at the office of the Board of Underwriters, where certificates with full details permitting the use of our light are filed by their own inspector. To light these lamps we run from one to three dynamos, according to the lamps in use at any given time, and we shall start additional dynamos as fast as we can connect more buildings. Neither as regards the loss due to resistance, nor as regards the number of lamps per horse-power, is there the slightest trouble or disappointment on the part of our company, and your correspondent is entirely in error is a.s.suming that there is. Let me suggest that if 'Investigator' really wishes to investigate, and is competent and willing to learn the exact facts, he can do so at this office, where there is no mystery of concealment, but, on the contrary, a strong desire to communicate facts to intelligent inquirers. Such a method of investigating must certainly be more satisfactory to one honestly seeking knowledge than that of first a.s.suming an error as the basis of a question, and then demanding an explanation.

"Yours very truly,

"S. B. EATON, President."

Viewed from the standpoint of over twenty-seven years later, the wisdom and necessity of answering anonymous newspaper letters of this kind might be deemed questionable, but it must be remembered that, although the Pearl Street station was working successfully, and Edison's comprehensive plans were abundantly vindicated, the enterprise was absolutely new and only just stepping on the very threshold of commercial exploitation. To enter in and possess the land required the confidence of capital and the general public. Hence it was necessary to maintain a constant vigilance to defeat the insidious attacks of carping critics and others who would attempt to injure the Edison system by misleading statements.

It will be interesting to the modern electrician to note that when this pioneer station was started, and in fact for some little time afterward, there was not a single electrical instrument in the whole station--not a voltmeter or an ammeter! Nor was there a central switchboard! Each dynamo had its own individual control switch. The feeder connections were all at the front of the building, and the general voltage control apparatus was on the floor above. An automatic pressure indicator had been devised and put in connection with the main circuits. It consisted, generally speaking, of an electromagnet with relays connecting with a red and a blue lamp. When the electrical pressure was normal, neither lamp was lighted; but if the electromotive force rose above a predetermined amount by one or two volts, the red lamp lighted up, and the attendant at the hand-wheel of the field regulator inserted resistance in the field circuit, whereas, if the blue lamp lighted, resistance was cut out until the pressure was raised to normal. Later on this primitive indicator was supplanted by the "Bradley Bridge," a crude form of the "Howell" pressure indicators, which were subsequently used for many years in the Edison stations.

Much could be added to make a complete pictorial description of the historic Pearl Street station, but it is not within the scope of this narrative to enter into diffuse technical details, interesting as they may be to many persons. We cannot close this chapter, however, without mention of the fate of the Pearl Street station, which continued in successful commercial operation until January 2, 1890, when it was partially destroyed by fire. All the "Jumbos" were ruined, excepting No.

9, which is still a venerated relic in the possession of the New York Edison Company. Luckily, the boilers were unharmed. Belt-driven generators and engines were speedily installed, and the station was again in operation in a few days. The uninjured "Jumbo," No. 9, again continued to perform its duty. But in the words of Mr. Charles L.

Clarke, "the glory of the old Pearl Street station, unique in bearing the impress of Mr. Edison's personality, and, as it were, constructed with his own hands, disappeared in the flame and smoke of that Thursday morning fire."

The few days' interruption of the service was the only serious one that has taken place in the history of the New York Edison Company from September 4, 1882, to the present date. The Pearl Street station was operated for some time subsequent to the fire, but increasing demands in the mean time having led to the construction of other stations, the mains of the First District were soon afterward connected to another plant, the Pearl Street station was dismantled, and the building was sold in 1895.

The prophetic insight into the magnitude of central-station lighting that Edison had when he was still experimenting on the incandescent lamp over thirty years ago is a little less than astounding, when it is so amply verified in the operations of the New York Edison Company (the successor of the Edison Electric Illuminating Company of New York) and many others. At the end of 1909 the New York Edison Company alone was operating twenty-eight stations and substations, having a total capacity of 159,500 kilowatts. Connected with its lines were approximately 85,000 customers wired for 3,813,899 incandescent lamps and nearly 225,000 horse-power through industrial electric motors connected with the underground service. A large quant.i.ty of electrical energy is also supplied for heating and cooking, charging automobiles, chemical and plating work, and various other uses.

CHAPTER XVII

OTHER EARLY STATIONS--THE METER

WE have now seen the Edison lighting system given a complete, convincing demonstration in Paris, London, and New York; and have noted steps taken for its introduction elsewhere on both sides of the Atlantic. The Paris plant, like that at the Crystal Palace, was a temporary exhibit. The London plant was less temporary, but not permanent, supplying before it was torn out no fewer than three thousand lamps in hotels, churches, stores, and dwellings in the vicinity of Holborn Viaduct. There Messrs.

Johnson and Hammer put into practice many of the ideas now standard in the art, and secured much useful data for the work in New York, of which the story has just been told.

As a matter of fact the first Edison commercial station to be operated in this country was that at Appleton, Wisconsin, but its only serious claim to notice is that it was the initial one of the system driven by water-power. It went into service August 15, 1882, about three weeks before the Pearl Street station. It consisted of one small dynamo of a capacity of two hundred and eighty lights of 10 c.p. each, and was housed in an unpretentious wooden shed. The dynamo-electric machine, though small, was robust, for under all the varying speeds of water-power, and the vicissitudes of the plant to which it, belonged, it continued in active use until 1899--seventeen years.

Edison was from the first deeply impressed with the possibilities of water-power, and, as this incident shows, was prompt to seize such a very early opportunity. But his attention was in reality concentrated closely on the supply of great centres of population, a task which he then felt might well occupy his lifetime; and except in regard to furnishing isolated plants he did not pursue further the development of hydro-electric stations. That was left to others, and to the application of the alternating current, which has enabled engineers to harness remote powers, and, within thoroughly economical limits, transmit thousands of horse-power as much as two hundred miles at pressures of 80,000 and 100,000 volts. Owing to his insistence on low pressure, direct current for use in densely populated districts, as the only safe and truly universal, profitable way of delivering electrical energy to the consumers, Edison has been frequently spoken of as an opponent of the alternating current. This does him an injustice. At the time a measure was before the Virginia legislature, in 1890, to limit the permissible pressures of current so as to render it safe, he said: "You want to allow high pressure wherever the conditions are such that by no possible accident could that pressure get into the houses of the consumers; you want to give them all the lat.i.tude you can." In explaining this he added: "Suppose you want to take the falls down at Richmond, and want to put up a water-power? Why, if we erect a station at the falls, it is a great economy to get it up to the city. By digging a cheap trench and putting in an insulated cable, and connecting such station with the central part of Richmond, having the end of the cable come up into the station from the earth and there connected with motors, the power of the falls would be transmitted to these motors. If now the motors were made to run dynamos conveying low-pressure currents to the public, there is no possible way whereby this high-pressure current could get to the public." In other words, Edison made the sharp fundamental distinction between high pressure alternating current for transmission and low pressure direct current for distribution; and this is exactly the practice that has been adopted in all the great cities of the country to-day. There seems no good reason for believing that it will change. It might perhaps have been altogether better for Edison, from the financial standpoint, if he had not identified himself so completely with one kind of current, but that made no difference to him, as it was a matter of conviction; and Edison's convictions are granitic.

Moreover, this controversy over the two currents, alternating and direct, which has become historical in the field of electricity--and is something like the "irrepressible conflict" we heard of years ago in national affairs--ill.u.s.trates another aspect of Edison's character.

Broad as the prairies and free in thought as the winds that sweep them, he is idiosyncratically opposed to loose and wasteful methods, to plans of empire that neglect the poor at the gate. Everything he has done has been aimed at the conservation of energy, the contraction of s.p.a.ce, the intensification of culture. Burbank and his tribe represent in the vegetable world, Edison in the mechanical. Not only has he developed distinctly new species, but he has elucidated the intensive art of getting $1200 out of an electrical acre instead of $12--a manured market-garden inside London and a ten-bushel exhausted wheat farm outside Lawrence, Kansas, being the antipodes of productivity--yet very far short of exemplifying the difference of electrical yield between an acre of territory in Edison's "first New York district" and an acre in some small town.

Edison's lighting work furnished an excellent basis--in fact, the only one--for the development of the alternating current now so generally employed in central-station work in America; and in the McGraw Electrical Directory of April, 1909, no fewer than 4164 stations out of 5780 reported its use. When the alternating current was introduced for practical purposes it was not needed for arc lighting, the circuit for which, from a single dynamo, would often be twenty or thirty miles in length, its current having a pressure of not less than five or six thousand volts. For some years it was not found feasible to operate motors on alternating-current circuits, and that reason was often urged against it seriously. It could not be used for electroplating or deposition, nor could it charge storage batteries, all of which are easily within the ability of the direct current. But when it came to be a question of lighting a scattered suburb, a group of dwellings on the outskirts, a remote country residence or a farm-house, the alternating current, in all elements save its danger, was and is ideal. Its thin wires can be carried cheaply over vast areas, and at each local point of consumption the transformer of size exactly proportioned to its local task takes the high-voltage transmission current and lowers its potential at a ratio of 20 or 40 to 1, for use in distribution and consumption circuits. This evolution has been quite distinct, with its own inventors like Gaulard and Gibbs and Stanley, but came subsequent to the work of supplying small, dense areas of population; the art thus growing from within, and using each new gain as a means for further achievement.

Nor was the effect of such great advances as those made by Edison limited to the electrical field. Every department of mechanics was stimulated and benefited to an extraordinary degree. Copper for the circuits was more highly refined than ever before to secure the best conductivity, and purity was insisted on in every kind of insulation.

Edison was intolerant of sham and shoddy, and nothing would satisfy him that could not stand cross-examination by microscope, test-tube, and galvanometer. It was, perhaps, the steam-engine on which the deepest imprint for good was made, referred to already in the remarks of Mr.

F. J. Sprague in the preceding chapter, but best ill.u.s.trated in the perfection of the modern high-speed engine of the Armington & Sims type.

Unless he could secure an engine of smoother running and more exactly governed and regulated than those available for his dynamo and lamp, Edison realized that he would find it almost impossible to give a steady light. He did not want his customers to count the heart-beats of the engine in the flicker of the lamp. Not a single engine was even within gunshot of the standard thus set up, but the emergency called forth its man in Gardiner C. Sims, a talented draughtsman and designer who had been engaged in locomotive construction and in the engineering department of the United States Navy. He may be quoted as to what happened: "The deep interest, financial and moral, and friendly backing I received from Mr. Edison, together with valuable suggestions, enabled me to bring out the engine; as I was quite alone in the world--poor--I had found a friend who knew what he wanted and explained it clearly. Mr.

Edison was a leader far ahead of the time. He compelled the design of the successful engine.

"Our first engine compelled the inventing and making of a suitable engine indicator to indicate it--the Tabor. He obtained the desired speed and load with a friction brake; also regulator of speed; but waited for an indicator to verify it. Then again there was no known way to lubricate an engine for continuous running, and Mr. Edison informed me that as a marine engine started before the ship left New York and continued running until it reached its home port, so an engine for his purposes must produce light at all times. That was a poser to me, for a five-hours' run was about all that had been required up to that time.

"A day or two later Mr. Edison inquired: 'How far is it from here to Lawrence; it is a long walk, isn't it?' 'Yes, rather.' He said: 'Of course you will understand I meant without oil.' To say I was deeply perplexed does not express my feelings. We were at the machine works, Goerck Street. I started for the oil-room, when, about entering, I saw a small funnel lying on the floor. It had been stepped on and flattened. I took it up, and it had solved the engine-oiling problem--and my walk to Lawrence like a tramp actor's was off! The eccentric strap had a round gla.s.s oil-cup with a bra.s.s base that screwed into the strap. I took it off, and making a sketch, went to Dave Cunningham, having the funnel in my hand to ill.u.s.trate what I wanted made. I requested him to make a sheet-bra.s.s oil-cup and solder it to the base I had. He did so. I then had a standard made to hold another oil-cup, so as to see and regulate the drop-feed. On this combination I obtained a patent which is now universally used."

It is needless to say that in due course the engine builders of the United States developed a variety of excellent prime movers for electric-light and power plants, and were grateful to the art from which such a stimulus came to their industry; but for many years one never saw an Edison installation without expecting to find one or more Armington & Sims high-speed engines part of it. Though the type has gone out of existence, like so many other things that are useful in their day and generation, it was once a very vital part of the art, and one more ill.u.s.tration of that intimate manner in which the advances in different fields of progress interact and co-operate.

Edison had installed his historic first great central-station system in New York on the multiple arc system covered by his feeder and main invention, which resulted in a notable saving in the cost of conductors as against a straight two-wire system throughout of the "tree" kind.

He soon foresaw that still greater economy would be necessary for commercial success not alone for the larger territory opening, but for the compact districts of large cities. Being firmly convinced that there was a way out, he pushed aside a ma.s.s of other work, and settled down to this problem, with the result that on November 20, 1882, only two months after current had been sent out from Pearl Street, he executed an application for a patent covering what is now known as the "three-wire system." It has been universally recognized as one of the most valuable inventions in the history of the lighting art. [13] Its use resulted in a saving of over 60 per cent. of copper in conductors, figured on the most favorable basis previously known, inclusive of those calculated under his own feeder and main system. Such economy of outlay being effected in one of the heaviest items of expense in central-station construction, it was now made possible to establish plants in towns where the large investment would otherwise have been quite prohibitive. The invention is in universal use today, alike for direct and for alternating current, and as well in the equipment of large buildings as in the distribution system of the most extensive central-station networks. One cannot imagine the art without it.

[Footnote 13: For technical description and ill.u.s.tration of this invention, see Appendix.]

The strong position held by the Edison system, under the strenuous compet.i.tion that was already springing up, was enormously improved by the introduction of the three-wire system; and it gave an immediate impetus to incandescent lighting. Desiring to put this new system into practical use promptly, and receiving applications for licenses from all over the country, Edison selected Brockton, Ma.s.sachusetts, and Sunbury, Pennsylvania, as the two towns for the trial. Of these two Brockton required the larger plant, but with the conductors placed underground.

It was the first to complete its arrangements and close its contract.

Mr. Henry Villard, it will be remembered, had married the daughter of Garrison, the famous abolitionist, and it was through his relationship with the Garrison family that Brockton came to have the honor of exemplifying so soon the principles of an entirely new art. Sunbury, however, was a much smaller installation, employed overhead conductors, and hence was the first to "cross the tape." It was specially suited for a trial plant also, in the early days when a yield of six or eight lamps to the horse-power was considered subject for congratulation. The town being situated in the coal region of Pennsylvania, good coal could then be obtained there at seventy-five cents a ton.

The Sunbury generating plant consisted of an Armington & Sims engine driving two small Edison dynamos having a total capacity of about four hundred lamps of 16 c.p. The indicating instruments were of the crudest construction, consisting of two voltmeters connected by "pressure wires"

to the centre of electrical distribution. One ammeter, for measuring the quant.i.ty of current output, was interpolated in the "neutral bus" or third-wire return circuit to indicate when the load on the two machines was out of balance. The circuits were opened and closed by means of about half a dozen roughly made plug-switches. [14] The "bus-bars" to receive the current from the dynamos were made of No. 000 copper line wire, straightened out and fastened to the wooden sheathing of the station by iron staples without any presence to insulation. Commenting upon this Mr. W. S. Andrews, detailed from the central staff, says: "The interior winding of the Sunbury station, including the running of two three-wire feeders the entire length of the building from back to front, the wiring up of the dynamos and switchboard and all instruments, together with bus-bars, etc.--in fact, all labor and material used in the electrical wiring installation--amounted to the sum of $90. I received a rather sharp letter from the New York office expostulating for this EXTRAVAGANT EXPENDITURE, and stating that great economy must be observed in future!" The street conductors were of the overhead pole-line construction, and were installed by the construction company that had been organized by Edison to build and equip central stations.

A special type of street pole had been devised by him for the three-wire system.

[Footnote 14: By reason of the experience gained at this station through the use of these crude plug-switches, Mr.

Edison started a compet.i.tion among a few of his a.s.sistants to devise something better. The result was the invention of a "breakdown" switch by Mr. W. S. Andrews, which was accepted by Mr. Edison as the best of the devices suggested, and was developed and used for a great many years afterward.]

Supplementing the story of Mr. Andrews is that of Lieut. F. J. Sprague, who also gives a curious glimpse of the glorious uncertainties and vicissitudes of that formative period. Mr. Sprague served on the jury at the Crystal Palace Exhibition with Darwin's son--the present Sir Horace--and after the tests were ended left the Navy and entered Edison's service at the suggestion of Mr. E. H. Johnson, who was Edison's shrewd recruiting sergeant in those days: "I resigned sooner than Johnson expected, and he had me on his hands. Meanwhile he had called upon me to make a report of the three-wire system, known in England as the Hopkinson, both Dr. John Hopkinson and Mr. Edison being independent inventors at practically the same time. I reported on that, left London, and landed in New York on the day of the opening of the Brooklyn Bridge in 1883--May 24--with a year's leave of absence.