CHAPTER III
A COLD SUBJECT
R. CURTIS let his hands drop helplessly by his side.
"So you actually think," said he, "that you can construct machinery that can work unharmed through lakes of molten matter?"
"Yes," answered Dr. Giles, "I am convinced that I can."
"And that you will be able to find, for workmen, human salamanders who can flit about in the fire unharmed by the scorching heat?"
Dr. Giles broke into a hearty laugh. "No," said he, shaking his head emphatically; "I claim no such power as that. I am convinced that I shall be able to construct fire-proof machinery, and that will be all I shall require. Of what use would it be to secure fire-proof workmen? If I were obliged to send my men down into the tube, I should, of course, need some protection for them, but I shall arrange my machinery so that it can be worked from above the earth."
"Even so, do you mean to tell me that machinery can be constructed that will pass unharmed through a sea of fire?"
"I think I would better explain the whole scheme to you in detail," observed Dr. Giles, "as otherwise there would be no end to your objections. To begin with, as I have already told you, I intend to have a metal tube cast and let down as the digging progresses; this tube will, of course, prevent any molten matter from entering my well from the sides."
"Yes, unless the tube itself melts."
"Precisely; and as this is what I wish to avoid, I shall, in casting the tube, provide it with internal passages such that refrigerating agents of the greatest power may be continually pumped through to keep the tube from melting."
"And you believe that you can obtain refrigerating agents of sufficient power to counteract the intense heat of the interior of the earth?"
"I am certain of it. For several years past I have been devoting considerable attention to the subject of accumulating cold, and I have at last succeeded in finding what I sought. I am now able to produce a temperature of about 425° F. below zero, and you will readily admit that a cold of this intensity can be made to offset any heat that I may meet with in my undertaking."
"But how do you manage to secure so great a degree of cold?" asked Mr. Curtis, somewhat skeptically.
"The details of the operation," said Dr. Giles, "would naturally be too complex to explain offhand, but the general principle on which I work is quite simple. To begin with, I suppose you are aware that, properly speaking, there is no such thing as cold. We say that ice is cold because it has considerably less heat than the human body. But ice nevertheless does possess heat, and quite a goodly amount of it, too. The only bodies which possess no heat whatever are those which are at a temperature of about 459° F. below zero. This is, to the best of our knowledge, the point of absolute cold, that is to say, the point at which a body will retain absolutely no heat at all. By no process that we know of can such absolute cold be produced,—although, as I have said, I have succeeded in coming very near to it."
"But how do you manage to obtain such a low temperature?" persisted Mr. Curtis.
"It was a hard problem," remarked Dr. Giles, "and my method is not easy to explain, but I shall do my best to make the matter clear to you. As you are aware, in order to cool a body, it is necessary to make it impart some of its heat to other bodies, and this is precisely what I have succeeded in doing. I put in my machine a gallon of specially prepared non-freezable liquid, and then pass a current of water at 50° F. through the apparatus. Every gallon of water that passes through becomes heated to 51° F. in its passage; in other words, it absorbs one degree of heat from the original liquid, so that the temperature of this liquid after ten gallons of water have passed through will be ten degrees lower than it was at first. By continuing the flow of water through the apparatus, this absorption of heat keeps on, at a slightly decreasing rate, until the temperature of the original liquid is lowered to 425° F. below zero. Beyond this point I have not yet succeeded in going, but 425° F. below zero is a temperature so inconceivably low that it will amply suffice for any practical application of cold."
"Well, doctor, you seem to have an answer for everything, although I must confess that I am only half convinced by your arguments. Still, even granting that you could bore your hole through the center of the earth, your scheme would yet seem impossible."
"How so?" asked Dr. Giles.
"Why, in this way. Let us suppose that you drop something into the hole; the object would merely fall to the center of the earth and stop there. It would then, of course, be half the way to New York, but to haul it up the last four thousand miles would require such expensive apparatus, and would be such a slow and laborious operation, that you would lose much more than you would gain."