CHAPTER L.--Ross's Second Voyage--The North Magnetic Pole--D'Urville--Enderby's Land--Back's Voyage in the Terror--The Great Western and Sirius--United States' Exploring Expedition--The Antarctic Continent--Sir John Franklin's Last Voyage in the Erebus and Terror--Efforts made to relieve him--Discovery of the Scene of his First Winter Quarters--The Grinnell Expedition--The Advance and Rescue--Lieutenant de Haven--Dr. Kane--Return of the Expedition 535 CHAPTER LI.--Kennedy's Expedition--Sir Edward Belcher--McClure--Discovery of the Northwest Passage--Junction of McClure and Kellett--Episode of the Resolute--Commodore Perry's Expedition--Decisive Traces of the Fate of Sir John Franklin--The Leviathan 553 CHAPTER LII.--The Second Grinnell Expedition--The Advance in Winter Quarters--Total Darkness--Sledge-Parties--Adventures--The First Death--Tennyson's Monument--Humboldt Glacier--The Open Polar Sea--Second Winter--Abandonment of the Brig--The Water again--Upernavik--Rescue by Captain Hartstene--Death and Services of Dr. Kane--Attempt to lay the Atlantic Cable 561 CHAPTER LIII.--Second and Third Attempts to lay the Atlantic Cable--The Failure in the Month of June--Description of the Cable--The Voyage of the Niagara--The Continuity--All Right again--Change from one Coil to Another--The Knights of the Black Hand--Unfavorable Symptoms--The Insulation broken--The Third of August--An Anxious Moment--Land discovered--Trinity Bay--Mr. Field visits the Telegraph Station--The Operators taken by Surprise--Landing of the Cable--Impressive Ceremony--Captain Hudson returns Thanks to Heaven--The Voyage of the Agamemnon--The Queen's Message--The Sixteenth of August--Deep-Sea Telegraphing--The Equator and the Cable 576 CHAPTER LIV.--Diving--The first diving-bell--Fixed apparatus supplied with compressed air--The submarine hydrostat--Operations at Hell Gate--Diving apparatus--Submarine explosions--Improved diving dresses--Their use--Work of various kinds done with them--Instances of this--Seeking the treasure of the Hussar--Sunken ships in Sebastopol--Operations in Mobile--The Dry Dock at Pensacola Bay--The beauties of the submarine world--Habits of the fish--Possible depth of descent 594 CHAPTER LV.--Fishing--The ocean as a field--The crops it yields--The sponge--Transplanting sponges--Coral fisheries--The coral an animal--The discovery of this--Oyster fishery--The oyster a social animal--The young oyster--Oyster culture--Dredging for oysters--The American oyster fishery--Pearl oysters--The value of the pearl fishery--Shark fishing--Cuttle fish 627