Alexander Mackenzie, filled with the sense of the importance of his discovery, determined to give it to the world, and spent the winter at Fort Chipewyan in preparing the material. In this he was much assisted by his cousin, Roderick McKenzie, to whom he sent the journal for revision and improvement. Early in the year 1794, the distinguished explorer left Lake Athabasca, journeyed over to Grand Portage, and a year afterward revisited his native land. He never returned to the "Upper Country," as the Athabasca region was called, but became one of the agents of the fur-traders in Montreal, never coming farther toward the North-west than to be present at the annual gatherings of the traders at Grand Portage. The veteran explorer continued in this position till the time when he crossed the Atlantic and published his well-known "Voyages from Montreal," dedicated to "His Most Sacred Majesty George the Third." The book, while making no pretensions to literary attainment, is yet a clear, succinct, and valuable account of the fur trade and his own expeditions. It was the work which excited the interest of Lord Selkirk in Rupert's Land and which has become a recognized authority. In 1801 this work of Alexander Mackenzie was published, and the order of knighthood was conferred upon the successful explorer. On his return to Canada, Sir Alexander engaged in strong opposition to the North-West Company and became a member of the Legislative Assembly for Huntingdon County, in Lower Canada. He lived in Scotland during the last years of his life, and died in the same year as the Earl of Selkirk, 1820. Thus passed away a man of independent mind and of the highest distinction. His name is fixed upon a region that is now coming into greater notice than ever before. CHAPTER XVI. THE GREAT EXPLORATION. Grand Portage on American soil--Anxiety about the boundary--David Thompson, astronomer and surveyor--His instructions--By swift canoe--The land of beaver--A dash to the Mandans--Stone Indian House--Fixes the boundary at Pembina--Sources of the Mississippi--A marvellous explorer--Pacific slope explored--Thompson down the Kootenay and Columbia--Fiery Simon Fraser in New Caledonia--Discovers Fraser River--Sturdy John Stuart--Thompson River--Bourgeois Quesnel--Transcontinental expeditions.