His own words are: "A vast platform crosses this distinguished supreme elevation, and, what is more astonishing, in the midst of it rises a lake. How is this lake formed? Whence do its waters proceed? This lake has no issue! And my eyes, which are not deficient in sharpness, cannot discover in the whole extent of the clearest and widest horizon any land which rises above it. All places around it are, on the contrary, considerably lower." Beltrami then went to examine the surrounding country, and found the lake, to which he gave the name of Lake Julia, to be bottomless. This lake he pronounces to be the source of the Mississippi River. This opinion was published abroad and accepted by some, but later explorations proved him to be wrong. A small lake to the south-west, afterwards found to be the true source, was described to him by his guide as Lac La Biche, and he placed this on his chart as "Doe Lake," the west source of the Mississippi. It is a curious fact that Lake Julia was the same lake surveyed twenty-five years before by astronomer Thompson. After further explorations, Beltrami returned to Fort Snelling, near St. Paul, Minn., being clothed in Indian garments, with a piece of bark for a hat. The intrepid explorer found his way to New Orleans, where he published "La Découverte des Sources du Mississippi." Though the work was criticized with some severity, yet Beltrami, on his arrival at London in 1827, published "A Pilgrimage in Europe and America" in two volumes, which are the source of our information. The county in Minnesota, which includes both Julia and Doe Lakes, is appropriately called Beltrami County. CASS AND SCHOOLCRAFT. Lewis Cass, of New Hampshire was appointed Governor of Michigan in 1813. Six years after this he addressed the Secretary of War in Washington, proposing an expedition to and through Lake Superior, and to the sources of the Mississippi. It was planned for an examination of the principal features of the North-West tributary to Lake Superior and the Mississippi River. This was sanctioned in 1820, and the expedition embarked in May of that year at Detroit, Michigan, Henry Schoolcraft being mineralogist, and Captain D. B. Douglas topographer and astronomer.