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
