"Yes, Bill; below the level of the sea."
"Great Erebus, I knew that we had descended a long way, but I would never have believed that we had gone down over two miles. Two miles, and more, below sea-level. That is a record-smasher."
"Rather," Milton smiled. "Before us no man (of our sunlit world) had penetrated into the crust of the earth to a greater depth than three thousand seven hundred and fifty-eight feet below the level of the sea. That is the depth of the mine at St. John del Rey, Minas Geraes, Brazil."
"Two miles—over two miles down!" said I.
"And probably, Bill, we are only just getting started."
"But the pressure. We can't go down very far into this steadily increasing pressure, increasing in a geometrical ratio whilst the depth increases only in an arithmetical one."
"But," Milton said, "I showed you that there is something wrong with the law."
"Then how do you know that we have reached a depth of twelve thousand feet and over, if the law breaks down?"
"I don't believe that it has broken down yet. It will hold good for this slight descent which we have made. And, of course, if fact is found to coincide with theory, then our descent will be arrested at no great depth."
"And," I said, "unless the discrepancy between fact and theory is a remarkable one, we will have no means of knowing whether the law has broken down or not. For it is impossible, in this world of utter darkness, to make anything like an accurate estimate of the descent made good."