CHAPTER VII
A SUBMARINE TRIP
"
HY, doctor, surely my ears deceive me! You don't actually mean to say that you are thinking of beginning operations at the bottom of the ocean?"
"Most assuredly I am."
"But what reasons have you for such a foolish step? Why do you wish to allow the ocean to run into your tunnel?"
"I think I shall have no difficulty in keeping the ocean out," said Dr. Giles, smiling.
"Well, but what advantage do you see in beginning work under water?"
"To begin with," said Dr. Giles, "there is the advantage you mentioned of having a convenient dumping-place for all the materials excavated."
"And I suppose, too, you will save a few miles of digging by beginning at a deep spot in the ocean instead of beginning on land?"
"That consideration," said Dr. Giles, laughing, "would not influence me in the least, for the difficulties of working under water would retard us far more than we should be helped by the mile or two we should gain. No; my main reason for commencing the work under water is a most imperative one, and one that I do not wish to talk about just yet. You may, however, rest assured that I have excellent reasons for beginning work in the ocean itself."
What those reasons were was seen only later.
Dr. Giles lost no time in putting his plans into practical operation. As we have already hinted, he began operations simultaneously in Australia and New York, so that the digging might proceed in both directions at once. In this way the work would occupy but one half of the time it would require were the start made only from one side.
The point selected for the operation in the eastern hemisphere was at about 40° south latitude and 110° east of Greenwich, near the southwestern coast of the Australian continent, about two hundred miles from shore; while on the American side the point selected was at about 40° north latitude and 70° longitude west of Greenwich—in other words, not far from the city of New York.
The work was begun in an immense chamber constructed under water; and to prevent the caving in of the walls of the tunnel as the digging progressed, a tube of considerable thickness and wonderful strength, made of the new metal, carbonite, was used. This metal, discovered—or, more properly speaking, invented—by the doctor, possessed all the qualities necessary for the purpose; for, while obtainable in large quantities, and easy to work, it had a strength compared with which the strength of the best steel was virtually nothing.
As it would have been out of the question to cast an eight-thousand-mile tube in a single piece, or, even if cast, to insert it afterward into the hole, some other plan had to be devised for accomplishing the desired result. But Dr. Giles had carefully studied out this part of the work, and by an admirable contrivance he had arranged to cast the tube little by little, immediately over the hole, and let it down as the boring progressed. In this way the top of the tube was always in a state of fusion, although the bottom was perfectly cold. 
"THE GIGANTIC MACHINE DEVISED FOR BORING THROUGH THE EARTH WAS A VERITABLE MASTERPIECE OF INVENTION."
As regards the gigantic machine devised for boring through the earth, it was a veritable masterpiece of invention, but so complicated in operation that it is impossible to give more than a general idea of its effects. The device used for excavating the first few hundred miles was somewhat in the style of an immense auger, which, by its rapid revolutions, loosened the earth and transported it automatically to the surface, where, after being carefully scrutinized by a geologist for its mineral wealth, it was dumped into the ocean to form a new island. To the great joy of the capitalists who had invested in the enterprise, it was found that the returns obtained from the sale of the mineral wealth brought up were considerable, while much valuable knowledge was gained as to the internal structure of the earth.
Whenever a stratum of solid rock was met with in the downward progress of the boring auger, this rock was first brought to a state of fusion by directing upon it jets of flame of exceedingly high temperature. The molten rock was then easily scooped up by special devices protected from the effects of the heat by refrigerating agents of great power, which were kept in rapid circulation through internal passages in the machinery.
The boring auger itself was so constructed that it continually descended as the hole deepened, and it was soon working far below the surface of the earth, the power that caused it to revolve being transmitted from above by means of electrical conductors.
Fastened near the bottom of the carbonite tube, along the interior, was an endless chain of fireproof buckets, which received the loose material thrown up by the auger, and emptied it into a second chain of buckets fastened somewhat higher up in the tube; and these emptied into a third chain, and so on until the loose material finally reached the surface of the earth. A new chain of buckets was added at the top each time the length of the tube was increased.
The work of excavation progressed at an astonishing speed, for the machinery was kept in splendid running order, and was so cunningly devised that any part which broke could at once be replaced by a new one, without its being necessary to stop the machine even for an instant.
The power required for the work had been furnished by the ocean itself, whose tides were "harnessed up" and pressed into service. This was the cheapest motive power that could be obtained, and it was withal efficient, easy to handle, and ample to perform many tasks like the one set it. As before mentioned, this power was converted into electricity and then carried down into the tube, along wires, to the points where it was required.
As the work advanced the difficulties increased. The greatest obstacle seemed to come from the internal heat of the earth; for in spite of what the doctor had said, the temperature rose with every mile's progress.
Mr. Curtis, who was always taking flying trips to the tube to see how matters were progressing and to give the doctor much unsought advice, was delighted when he noticed this steady increase of temperature.
"What did I tell you?" he cried, his eyes beaming with pleasure at the fulfilment of his prophecy. "I guess you'll soon have to set your refrigerating liquids circulating through the tube if you want to keep it from melting."
"I have given up that idea of pumping cold liquids through the tube," replied the doctor.
"The experiments I made in that line have convinced me that such a device would not be practicable on a tube of the great length this one will have. I have, however, found a plan, on much the same principle, that promises to give far better results than the other."
"I thought it was only pretty women who were allowed to chenge their minds," said Mr. Curtis, smiling.
"Pretty women and intelligent men," retorted Dr. Giles. "A man who has n't sense enough to change his mind when he has a good reason for doing so, is little better than a fool. A truly scientific man is always ready to give up one idea for a better one."
"Well, then, tell me your new idea, I beg, that I may see if it is in keeping with the rest of your absurd plan."
"I have n't time to go into much detail," said the doctor, "but I can briefly explain it to you in outline."
"Please do, and make your explanation as simple as you can. I always like explanations that are clear and easy to understand."
"All right. Now, in the present case, the problem is simply this: The heat has been steadily increasing the farther down we get into the interior of the earth, and it threatens to continue increasing in the same manner for some time to come. As this heat might injure the tube, I shall be forced to remove it in some way."
"Remove the heat?" said Mr. Curtis, inquiringly.
"Of course; the only way to get rid of heat is to remove it."
"But in your first plan of pumping cold liquids through the tube, you did n't remove any heat."
"If that plan had been adopted it would most certainly have resulted in removing the heat, and that is precisely where its weak point lies. The heat would have passed into the cold liquids, and these would soon have become so hot that the pumping operations would have had to be on a gigantic scale to keep the tube at the proper temperature."
"Ah! and what is your new plan?"
"My new plan is simply to transform the internal heat into electricity, and then carry off this electricity from the tube by means of special conductors."
""What!" exclaimed Mr. Curtis, "you think you will be able to change the heat into electricity?"
"Certainly," said Dr. Giles. "Did you not know that heat, force, light, and electricity are really all the same thing under different forms, and that one can be readily converted into the other? Every day we change heat into force, light, or electricity, and vice versa, so that what I propose to do here is merely what the world has been doing for many years."
"Well, go on," said Mr. Curtis.
"There is nothing further to say, but simply this, that, in casting the tube, I have so prepared both the outer and the inner surface that any heat above 70° F. will at once be changed into electricity by a secret process of my own devising. This electricity instantaneously passes to my office along the conductors mentioned. As you are aware, electrical energy travels so fast that it can go eight times around the earth in a single second; you will therefore see that, so long as I can use up this energy as fast as it reaches me, the tube cannot acquire a temperature much above 70° F. As soon as the heat becomes greater than this, the excess is at once converted into electrical energy and instantaneously passes to my office."
"But how do you get rid of all this electricity that accumulates in your office?" queried Mr. Curtis.
"I sell it."
"You sell it!"
"Yes; I have had special wires laid to the Australian shore; and what electrical energy I do not myself use for my boring operations, I transmit to Australia and sell to different parties there to run the machinery of their factories, draw their cars, light their houses, cook their dinners, and perform innumerable other operations. I have contracts at very remunerative figures for all the electrical power I can possibly furnish."
Mr. Curtis was nonplussed. "Well, that does beat everything!" he exclaimed. "It is beyond my comprehension how practical business men can be such fools as to pin their faith on an enterprise of this kind, and make contracts for electricity dug up from the center of the earth."
Dr. Giles laughed. "You'll be more astonished yet," he said, "before I finish this job I have undertaken. But that reminds me that, if you want to see something interesting, you'd better come along with me, and take a look at my submarine houses. I think that Flora, too, would like to see them."
"Oh, yes, indeed," said the young girl, who had been intently listening to the conversation. "I find everything so interesting down here, and you make matters so plain to me."
"Well, come along, then," said the doctor; and he led the way into an adjoining room which could be hermetically shut off from the other parts of the caisson.
"There is our boat," he remarked, pointing to a large submarine vessel resting on its keel in the middle of the room.
A hatchway at the top of the boat was wide open, and through this Flora could see that the interior was upholstered in the most gorgeous style, and was provided with every modern improvement.
"Oh, what a pretty place!" she exclaimed, delighted. "Those colored electric lights make it seem like fairy-land, and it is furnished like a king's palace!"
"Yes," said Dr. Giles; "I had this boat built expressly for receiving state guests who come to visit the works. It has already carried several royal personages, but although good enough for kings and queens, it is none too good for you, Flora." And Dr. Giles pinched her cheek mischievously.
After the party had taken their places, the hatchway was closed, water was admitted to the outer chamber, and communication opened with the ocean. The pressure of a button set the machinery in operation, and the boat, propelled by a powerful dynamo, was soon speeding along beneath the surface of the sea.
Glass windows formed the sides and top of the vessel, and powerful search-lights illuminated the surrounding ocean, so that to Flora it was a veritable trip in fairy-land to pass through these wonderful regions inhabited by fish and other marine animals of the most curious shapes.
All too soon they reached the spot where the submarine houses were being erected, some already completed, others just begun. It was truly weird to see the workmen in their divingsuits engaged in the construction of these habitations, and Flora did not tire of watching them. Mr. Curtis, too, was interested, but he was puzzled as well.
"I must say, doctor," said he, in a tone of perplexity, "that I don't at all understand what you need these submarine houses for. Where do your workmen lodge at present?"
"Most of them return to Australia after their day's work is done," replied Dr. Giles, "but a number of them sleep in the caisson where the digging operations are carried on."
"Then, why is it they cannot continue to sleep there, instead of your being obliged to go to the expense of constructing these extra habitations?"
"For the simple reason," said Dr. Giles, "that if I failed to take this very elementary precaution, my workmen might pay the penalty with their lives."