PART II
For all the long hot weeks of the next summer Dora worked faithfully every day on the hotel lamps. She had to be at her work at eight o'clock every morning, and she seldom finished before two in the afternoon. But every week her uncle paid her three dollars and a half, and by the end of the season she had forty-two dollars carefully put away. When the hotel closed, her uncle made her a present of eight dollars, so that when she started for school in the fall she rejoiced in the thought of fifty dollars put away in the savings bank as a college fund.
She was happy, too, in the prospect of making as much money the next summer. For the Wizard, Uncle John told her, had not the secret yet. He had succeeded in making a platinum wire, encased in a glass globe, give a light equal to that of twenty-five candles without melting. But he needed to exhaust all the air from the glass globe, and still one one-hundred-thousandth of the original volume remained.
"But that's not sufficient," commented Uncle John. "I know enough about the matter to be sure that so much air as that would prevent the platinum from giving out the light it ought to give. Still, within a short time, Dora, I expect even the Portland papers will describe Mr. Edison's success with the electric light."
Uncle John's prediction was fulfilled. By the first of October the vacuum was so nearly perfect that only one-millionth part of the original air was left in the glass bulb. By the last of that same month, moreover, the whole secret was practically in Edison's grasp. He had stopped experimenting with platinum for a burner and had gone back to carbon, on which he had pinned his faith at first.
But this time he used the carbon only as a coating for a piece of cotton thread that he had bent into a loop and sealed up in the almost perfect vacuum of glass. When this lamp was connected with the battery, it flashed forth with the brightness that the inventor had so long waited to see. But how long would it burn? There was no sleep for Edison till that question was answered; and it was not answered for forty hours—nearly two days of growing delight and diminishing anxiety.
Such a discovery meant the end of all fruitless experimenting. The secret of the incandescent light was revealed; and the newspapers all over the country—the Daily Eastern Argus of Portland among them—spread the knowledge of the great event in science and prophesied the speedy conquest of kerosene and gas. Late in November Uncle John sent Dora a copy of the Scientific American which gave the authoritative account of what had been accomplished.
Edison in his Library.
"But," wrote Uncle John in the letter accompanying the paper, "now the real work has only begun. The Wizard knows that some carbonized material is what he needs, but he is sure that carbonized cotton thread is not the best thing. Now he is carbonizing everything he can lay his hands on—straw, tissue paper, soft paper, all kinds of cardboard, all kinds of threads, fish line, threads rubbed with tarred lampblack, fine threads plaited together in strands, cotton soaked in boiling tar, lamp wick, twine, tar and lampblack mixed, and many other materials that I can't remember. Why," finished Uncle John, "so far he has examined no fewer than six thousand different species of vegetable growth alone. Somebody said something to him the other day about his wonderful genius. 'Well,' modestly answered the great man, mopping his forehead with his handkerchief, 'genius, I think, is one per cent inspiration and ninety-nine per cent perspiration.'"
In December there came into Dora's life the most happy and exciting experience of her childhood. The letter from Uncle John in November had ended with this paragraph:
"I am looking forward to my visit to Maine next month, but I'm sorry to say it must be earlier and shorter than usual. I have an important engagement here for the twenty-fourth, and I'm planning to reach Maine on Saturday, the twentieth, spend Sunday with you, and leave there the twenty-second. But I have thought of a way of making my visit last longer and of giving you a new kind of Christmas present. That way is to take you back with me to Jersey and let you see what Christmas and New Year's in the neighborhood of New York are like. If you approve my new idea for Christmas, I want you to let me know at once."
If any twelve-year-old child who lives fifty miles from a city and has never been farther from home than that city in her life is reading this, she will know how Dora felt at the prospect of such a Christmas journey, and she will understand, too, how Dora had her answer ready for the post office in less than an hour after she had read her letter.
The only event of Dora's wonderful vacation that this story has a right to tell is her visit to Mr. Edison. It happened that in the Herald Uncle John bought as the train was nearing New York, there was a long article describing the lighting system that Mr. Edison had put into successful operation at Menlo Park. "Interest is getting so great in the incandescent light," remarked Uncle John, "that I shouldn't wonder if Mr. Edison let the public see it in operation. If he does, you and I are going to Menlo Park."
The prophecy was a true one. On New Year's Mr. Edison opened his grounds to the public, the railroad ran special trains, and over three thousand people visited Menlo Park. Here is the enthusiastic letter that Dora wrote next day to Maine:
Newark, N. J.
Jan. 1, 1880Dear Father and Mother,
I have been to Fairyland. The enclosed clippings will tell you all about it. I saw the king of the fairies too—I mean Mr. Edison—and he said, "Good evening, little girl," to me. He talked with Uncle John quite a while, and I heard all they said. Some one asked Mr. Edison when New York would be lighted by electricity and he answered, "I'm working night and day, but you see I have to produce not only a practicable lamp, but a whole system. I haven't found the best material for filaments yet, and there's not a place in the world where I can buy the dynamos (those are machines for making the electricity, Uncle John told me) and the smaller appliances."
Then Uncle John said, "Well, Edison, I'm waiting patiently till you make electric lights cheap enough for me to wire my hotel on the Maine coast. Can you make a prediction?"
"None that's safe," Edison answered. "You know the opposition of the gas companies, and you know the present high cost of the experiments. I've spent already over forty thousand dollars without returns, and my lamps are costing almost two dollars apiece. The public won't take them till they can be sold for forty cents or less. Moreover, I'm not satisfied with my paper carbon lamps. No, there is much work left; but I shall work day and night till New York has a central station and every appliance we need is manufactured at small cost."
"I suppose eating and sleeping don't bother you much just now," some one said.
"Not very much," answered Edison. "I eat when I'm hungry, and I sleep when I have to. Four hours a night are enough, for I can go to sleep instantly, and I always wake up rested."
Uncle John says that Mr. Edison is the greatest inventor the world has known. Just think of that! And I have seen him!
Yours affectionately,
Dora
Here are two newspaper clippings that Dora enclosed in her letter:
I
A NIGHT WITH EDISON
Menlo Park, N. J.
Dec. 30, 1879All day long and until late this evening, Menlo Park has been thronged with visitors coming from all directions to see the wonderful "electric light." Nearly every train that stopped brought delegations of sightseers till the depot was overrun and the narrow plank walk leading to the laboratory became alive with people. In the laboratory the throngs practically took possession of everything in their eager curiosity to learn all about the great invention. Four new street lamps were added last night, making six in all, which now give out the horse shoe light in the open air. Their superiority to gas is so apparent, both in steadiness and beauty of illumination, that every one is struck with admiration.
II
The afternoon trains brought some visitors, but in the evening every train set down a couple of score, at least. The visitors never seemed to tire of lighting the lamps upon the two main tables by simply laying one between the two long wires. Most were content to ejaculate "Wonderful!" But no amount of explanation would persuade one old gentleman that it was not an iron wire that was inside the glass tube. "It could not be the carbon filament of a piece of paper, for," said he, "I have seen some red hot, white hot iron wire, only it was not quite so bright, but it looked just like that. That's no filament!"
"This is a bad time for sceptics," I said to Edison.
"There are some left," he answered. "They die harder than a cat or a snake."
Dora's New York visit colored all the next five years that she worked and waited for college. Her interest in the electric light never wavered for an instant. Like many another, she marveled at the thoroughness of Mr. Edison's search for the right sort of filament and followed expectantly reports of those men whom he sent around the world in search of it.
She read with a bit of almost personal pride the item in the Portland paper that told how, on September 4, 1882, at three o'clock in the afternoon, electric light was supplied for the first time to a number of New York customers; and when, in 1884, that same paper stated that at Brockton, Massachusetts, the first theater ever lighted by electricity from a central plant had been thrown open, she wrote her uncle:
"I'm sure you'll have to discharge your lamp trimmer pretty soon. But I don't care now, for with father's help, I think I can enter Wellesley in the fall. Of course I hope to work one more summer for you."
Uncle John answered that letter in person, for he needed to go to Maine to make arrangements for the summer.
"I congratulate you, Dora," said he. "You deserve a college course. But I shan't discharge you yet. I expect now to wire the hotel by 1889; but even if I shouldn't need a lamp trimmer all the time till then, I shall always be glad of a capable waitress.—Will you work for me the next three summers?"
"Of course I will, Uncle John," replied Dora as eagerly and gratefully as she had made the same reply six years before. "With the money I can earn the next three summers, I can lessen college expenses a good deal."
So it happened that the ambition of Dora's girlhood; largely through her own pluck and persistence, was realized in due season. Still, she always felt that Mr. Edison unknowingly had a large share in the making of her career; for when in after years she became an instructor in physics at an influential school, she could easily trace back her love for her subject to her interest in the early experiments upon the electric light.