That day the Nautilus crossed an odd part of the Atlantic Ocean. No one is unaware of the existence of that great warm-water current known by name as the Gulf Stream. After emerging from channels off Florida, it heads toward Spitzbergen. But before entering the Gulf of Mexico near latitude 44 degrees north, this current divides into two arms; its chief arm makes for the shores of Ireland and Norway while the second flexes southward at the level of the Azores; then it hits the coast of Africa, sweeps in a long oval, and returns to the Caribbean Sea. Now then, this second arm—more accurately, a collar—forms a ring of warm water around a section of cool, tranquil, motionless ocean called the Sargasso Sea. This is an actual lake in the open Atlantic, and the great current’s waters take at least three years to circle it. Properly speaking, the Sargasso Sea covers every submerged part of Atlantis. Certain authors have even held that the many weeds strewn over this sea were torn loose from the prairies of that ancient continent. But it’s more likely that these grasses, algae, and fucus plants were carried off from the beaches of Europe and America, then taken as far as this zone by the Gulf Stream. This is one of the reasons why Christopher Columbus assumed the existence of a New World. When the ships of that bold investigator arrived in the Sargasso Sea, they had great difficulty navigating in the midst of these weeds, which, much to their crews’ dismay, slowed them down to a halt; and they wasted three long weeks crossing this sector. Such was the region our Nautilus was visiting just then: a genuine prairie, a tightly woven carpet of algae, gulfweed, and bladder wrack so dense and compact a craft’s stempost couldn’t tear through it without difficulty. Accordingly, not wanting to entangle his propeller in this weed-choked mass, Captain Nemo stayed at a depth some meters below the surface of the waves. The name Sargasso comes from the Spanish word “sargazo,” meaning gulfweed. This gulfweed, the swimming gulfweed or berry carrier, is the chief substance making up this immense shoal. And here’s why these water plants collect in this placid Atlantic basin, according to the expert on the subject, Commander Maury, author of The Physical Geography of the Sea. The explanation he gives seems to entail a set of conditions that everybody knows: “Now,” Maury says, “if bits of cork or chaff, or any floating substance, be put into a basin, and a circular motion be given to the water, all the light substances will be found crowding together near the center of the pool, where there is the least motion. Just such a basin is the Atlantic Ocean to the Gulf Stream, and the Sargasso Sea is the center of the whirl.”