Karl asks, “What was Pytheas’ ship like?”

“Well, it wasn’t really a ship. It was more of a large boat. It was only thirty meters long, three meters wide and it had just one square sail. On board, it had a crew of fifty oarsmen. At the most northern part of the voyage, Pytheas found that the boat had become a block of ice. He saw the sea around him become thicker, and noticed that it changed color and gave off smoke, and that the oars were dipping into a soup-like liquids that grew more and more dense. He was terrified and changed course. Several years later, when he had returned to Marseilles, he described the phenomenon. And that was the first scientific report on pack ice! And just think, twenty-three centuries later, on August 3rd, 1958 an American atomic submarine passed under the ice above the North Pole, quite safely.”

“An atomic submarine!” exclaims Karl in amazement.

“Yes, the Nautilus, a nuclear powered submarine. Its fuel was the energy produced by a small sphere of uranium! It was capable of going around the world three times without coming up to the surface!