<P> Various officers on the expedition, including William Bligh, George Vancouver, and John Gore, thought the existence of a route was' improbable' . Before reaching 65 ° N they found the coastline pushing them further south, but Gore convinced Cook to sail on into the Cook Inlet in the hope of finding the route . They continued to the limits of the Alaskan peninsula and the start of the 1,200 mi (1,900 km) chain of Aleutian Islands . Despite reaching 70 ° N, they encountered nothing but icebergs . </P> <P> From 1792 to 1794, the Vancouver Expedition (led by George Vancouver who had previously accompanied Cook) surveyed in detail all the passages from the Northwest Coast . He confirmed that there was no such passage south of the Bering Strait . This conclusion was supported by the evidence of Alexander MacKenzie, who explored the Arctic and Pacific oceans in 1793 . </P> <P> In the first half of the 19th century, some parts of the Northwest Passage (north of the Bering Strait) were explored separately by many expeditions, including those by John Ross, Elisha Kent Kane, William Edward Parry, and James Clark Ross; overland expeditions were also led by John Franklin, George Back, Peter Warren Dease, Thomas Simpson, and John Rae . In 1826 Frederick William Beechey explored the north coast of Alaska, discovering Point Barrow . </P> <P> Sir Robert McClure was credited with the discovery of the Northwest Passage in 1851 when he looked across McClure Strait from Banks Island and viewed Melville Island . However, this strait was not navigable to ships at that time . The only usable route linking the entrances of Lancaster Sound and Dolphin and Union Strait was discovered by John Rae in 1854 . </P>

Who traveled north along the north american coast before exploring newfoundland