below the horizon line, a Fata Morgana can cause the image of it to be elevated, and then everything which is seen by the observer is a mirage. On the other hand, if the real ship is still above the horizon, the image of it can be duplicated many times and elaborately distorted by a Fata Morgana. Phantom islands In the 19th and early 20th centuries, Fata Morgana mirages may have played a role in a number of unrelated "discoveries" of arctic and antarctic land masses which were later shown not to exist. Icebergs frozen into the pack ice, or the uneven surface of the ice itself, may have contributed to the illusion of distant land features. Sannikov Land Yakov Sannikov and Matvei Gedenschtrom claimed to have seen a land mass north of Kotelny Island during their 1809–1810 cartographic expedition to the New Siberian Islands. Sannikov reported this sighting of a "new land" in 1811, and the supposed island was named after him. Three-quarters of a century later, in 1886, Baron Eduard Toll, a Baltic German explorer in Russian service, reported observing Sannikov Land during another expedition to the New Siberian Islands. In 1900, he would lead still another expedition to the region, which had among its objectives the location and exploration of Sannikov Land. The expedition was unsuccessful in this respect. Toll and three others were lost after they departed their ship, which was stuck in ice for the winter, and embarked on a risky expedition by dog sled. In 1937, the Soviet icebreaker Sadko also tried and failed to find Sannikov Land. Some historians and geographers have theorised that the land mass that Sannikov and Toll saw was actually Fata Morganas of Bennett Island. Croker Mountains In 1818, Sir John Ross led an expedition to discover the long-sought-after Northwest Passage. When he reached Lancaster Sound in Canada, he sighted, in the distance, a land mass with mountains, directly ahead in the ship's course. He named the mountain range the Croker Mountains, after First Secretary to the Admiralty John Wilson Croker, and ordered the ship to turn around and return to England. Several of his officers protested, including First Mate William Edward Parry and Edward Sabine, but they could not dissuade him. The account of Ross's voyage, published a year later, brought to light this disagreement, and the ensuing controversy over the existence of the Croker Mountains ruined Ross's