"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
