Edison: His Life and Inventions

by Frank Lewis Dyer; Thomas Commerford Martin

At the award of the John Fritz gold medal in April, 1909, to Charles T. Porter for his work in advancing the knowledge of steam-engineering, and for improvements in engine construction, Mr. Frank J. Sprague spoke on behalf of the American Institute of Electrical Engineers of the debt of electricity to the high-speed steam-engine. He recalled the fact that at the French Exposition of 1867 Mr. Porter installed two Porter-Allen engines to drive electric alternating-current generators for supplying current to primitive lighthouse apparatus. While the engines were not directly coupled to the dynamos, it was a curious fact that the piston speeds and number of revolutions were what is common to-day in isolated direct-coupled plants. In the dozen years following Mr. Porter built many engines with certain common characteristics—i.e., high piston speed and revolutions, solid engine bed, and babbitt-metal bearings; but there was no electric driving until 1880, when Mr. Porter installed a high-speed engine for Edison at his laboratory in Menlo Park. Shortly after this he was invited to construct for the Edison Pearl Street station the first of a series of engines for so-called "steam-dynamos," each independently driven by a direct-coupled engine. Mr. Sprague compared the relations thus established between electricity and the high-speed engine not to those of debtor and creditor, but rather to those of partners—an industrial marriage—one of the most important in the engineering world. Here were two machines destined to be joined together, economizing space, enhancing economy, augmenting capacity, reducing investment, and increasing dividends.

While rapid progress was being made in this and other directions, the wheels of industry were humming merrily at the Edison Tube Works, for over fifteen miles of tube conductors were required for the district, besides the boxes to connect the network at the street intersections, and the hundreds of junction boxes for taking the service conductors into each of the hundreds of buildings. In addition to the immense amount of money involved, this specialized industry required an enormous amount of experiment, as it called for the development of an entirely new art. But with Edison's inventive fertility—if ever there was a cross-fertilizer of mechanical ideas it is he—and with Mr. Kruesi's never-failing patience and perseverance applied to experiment and evolution, rapid progress was made. A franchise having been obtained from the city, the work of laying the underground conductors began in the late fall of 1881, and was pushed with almost frantic energy. It is not to be supposed, however, that the Edison tube system had then reached a finality of perfection in the eyes of its inventor. In his correspondence with Kruesi, as late as 1887, we find Edison bewailing the inadequacy of the insulation of the conductors under twelve hundred volts pressure, as for example: "Dear Kruesi,—There is nothing wrong with your present compound. It is splendid. The whole trouble is air-bubbles. The hotter it is poured the greater the amount of air-bubbles. At 212 it can be put on rods and there is no bubble. I have a man experimenting and testing all the time. Until I get at the proper method of pouring and getting rid of the air-bubbles, it will be waste of time to experiment with other asphalts. Resin oil distils off easily. It may answer, but paraffine or other similar substances must be put in to prevent brittleness, One thing is certain, and that is, everything must be poured in layers, not only the boxes, but the tubes. The tube itself should have a thin coating. The rope should also have a coating. The rods also. The whole lot, rods and rope, when ready for tube, should have another coat, and then be placed in tube and filled. This will do the business." Broad and large as a continent in his ideas, if ever there was a man of finical fussiness in attention to detail, it is Edison. A letter of seven pages of about the same date in 1887 expatiates on the vicious troubles caused by the air-bubble, and remarks with fine insight into the problems of insulation and the idea of layers of it: "Thus you have three separate coatings, and it is impossible an air-hole in one should match the other."

To a man less thorough and empirical in method than Edison, it would have been sufficient to have made his plans clear to associates or subordinates and hold them responsible for accurate results. No such vicarious treatment would suit him, ready as he has always been to share the work where he could give his trust. In fact he realized, as no one else did at this stage, the tremendous import of this novel and comprehensive scheme for giving the world light; and he would not let go, even if busy to the breaking-point. Though plunged in a veritable maelstrom of new and important business interests, and though applying for no fewer than eighty-nine patents in 1881, all of which were granted, he superintended on the spot all this laying of underground conductors for the first district. Nor did he merely stand around and give orders. Day and night he actually worked in the trenches with the laborers, amid the dirt and paving-stones and hurry-burly of traffic, helping to lay the tubes, filling up junction-boxes, and taking part in all the infinite detail. He wanted to know for himself how things went, why for some occult reason a little change was necessary, what improvement could be made in the material. His hours of work were not regulated by the clock, but lasted until he felt the need of a little rest. Then he would go off to the station building in Pearl Street, throw an overcoat on a pile of tubes, lie down and sleep for a few hours, rising to resume work with the first gang. There was a small bedroom on the third floor of the station available for him, but going to bed meant delay and consumed time. It is no wonder that such impatience, such an enthusiasm, drove the work forward at a headlong pace.

Edison says of this period: "When we put down the tubes in the lower part of New York, in the streets, we kept a big stock of them in the cellar of the station at Pearl Street. As I was on all the time, I would take a nap of an hour or so in the daytime—any time—and I used to sleep on those tubes in the cellar. I had two Germans who were testing there, and both of them died of diphtheria, caught in the cellar, which was cold and damp. It never affected me."

It is worth pausing just a moment to glance at this man taking a fitful rest on a pile of iron pipe in a dingy building. His name is on the tip of the world's tongue. Distinguished scientists from every part of Europe seek him eagerly. He has just been decorated and awarded high honors by the French Government. He is the inventor of wonderful new apparatus, and the exploiter of novel and successful arts. The magic of his achievements and the rumors of what is being done have caused a wild drop in gas securities, and a sensational rise in his own electric-light stock from $100 to $3500 a share. Yet these things do not at all affect his slumber or his democratic simplicity, for in that, as in everything else, he is attending strictly to business, "doing the thing that is next to him."

Part of the rush and feverish haste was due to the approach of frost, which, as usual in New York, suspended operations in the earth; but the laying of the conductors was resumed promptly in the spring of 1882; and meantime other work had been advanced. During the fall and winter months two more "Jumbo" dynamos were built and sent to London, after which the construction of six for New York was swiftly taken in hand. In the month of May three of these machines, each with a capacity of twelve hundred incandescent lamps, were delivered at Pearl Street and assembled on the second floor. On July 5th—owing to the better opportunity for ceaseless toil given by a public holiday—the construction of the operative part of the station was so far completed that the first of the dynamos was operated under steam; so that three days later the satisfactory experiment was made of throwing its flood of electrical energy into a bank of one thousand lamps on an upper floor. Other tests followed in due course. All was excitement. The field-regulating apparatus and the electrical-pressure indicator—first of its kind—were also tested, and in turn found satisfactory. Another vital test was made at this time—namely, of the strength of the iron structure itself on which the plant was erected. This was done by two structural experts; and not till he got their report as to ample factors of safety was Edison reassured as to this detail.

A remark of Edison, familiar to all who have worked with him, when it is reported to him that something new goes all right and is satisfactory from all points of view, is: "Well, boys, now let's find the bugs," and the hunt for the phylloxera begins with fiendish, remorseless zest. Before starting the plant for regular commercial service, he began personally a series of practical experiments and tests to ascertain in advance what difficulties would actually arise in practice, so that he could provide remedies or preventives. He had several cots placed in the adjoining building, and he and a few of his most strenuous assistants worked day and night, leaving the work only for hurried meals and a snatch of sleep. These crucial tests, aiming virtually to break the plant down if possible within predetermined conditions, lasted several weeks, and while most valuable in the information they afforded, did not hinder anything, for meantime customers' premises throughout the district were being wired and supplied with lamps and meters.

On Monday, September 4, 1882, at 3 o'clock, P.M., Edison realized the consummation of his broad and original scheme. The Pearl Street station was officially started by admitting steam to the engine of one of the "Jumbos," current was generated, turned into the network of underground conductors, and was transformed into light by the incandescent lamps that had thus far been installed. This date and event may properly be regarded as historical, for they mark the practical beginning of a new art, which in the intervening years has grown prodigiously, and is still increasing by leaps and bounds.

Everything worked satisfactorily in the main. There were a few mechanical and engineering annoyances that might naturally be expected to arise in a new and unprecedented enterprise; but nothing of sufficient moment to interfere with the steady and continuous supply of current to customers at all hours of the day and night. Indeed, once started, this station was operated uninterruptedly for eight years with only insignificant stoppage.

It will have been noted by the reader that there was nothing to indicate rashness in starting up the station, as only one dynamo was put in operation. Within a short time, however, it was deemed desirable to supply the underground network with more current, as many additional customers had been connected and the demand for the new light was increasing very rapidly. Although Edison had successfully operated several dynamos in multiple arc two years before—i.e., all feeding current together into the same circuits—there was not, at this early period of experience, any absolute certainty as to what particular results might occur upon the throwing of the current from two or more such massive dynamos into a great distributing system. The sequel showed the value of Edison's cautious method in starting the station by operating only a single unit at first.