A great Exposition of the arts and industries of the whole wide world is to be held this summer in the beautiful city of Portland, Oregon. It is to commemorate the grand achievement of a few brave men and one brave woman, who lived, labored, and conquered a century ago. At the call of their commander, they exiled themselves from home and friends; they crossed the wide deserts, climbed through gorges and peaks of the "great Stony Mountains," struggled through the pathless forests of giant firs, lived among wild beasts, and wilder men, until they reached the pathless Pacific Ocean--that was then but a waste of water, where great whales sported and the seals found abundance of food amid rocky shores and islands for safe homes. Now teeming multitudes inhabit the fertile plains; through the rugged mountains pass the great highways of the world--along the charted coast are many ports, where white-winged fleets lie at anchor and the great black freighters load and unload the commerce of many lands. But Portland still retains many of the old landmarks. The beautiful Columbia River still flows by it to the sea, forests are not far away, and "the everlasting hills" are about it, with their white-capped peaks piercing the sky. A hundred years ago, a vast and unknown wilderness stretched from the Mississippi to the Pacific Ocean--it was a land of mystery of unknown extent. Millions of wild cattle that we call buffaloes roamed over its plains, wild beasts hid away in its mountain fastnesses, the beavers and otters built their homes along its rivers, and wild tribes of savage men made pitiless war upon each other, though not destitute of many noble traits of character. The young republic of United States had far more territory east of the Mississippi than they could manage or protect, so gave small care or thought to what lay beyond. But one thing they had learned, that, for their own safety from foreign aggression, and the protection of their commerce, they must gain possession and control of the great river. Thomas Jefferson, that wise and far-seeing statesman whose name and fame grow as the years go on, was President at that memorable time of great opportunities, and through his influence with Congress induced them to make the great Louisiana purchase, which gave to our government the Southern and Gulf states, the control of the Mississippi River, and, as Jefferson believed and claimed, the whole country to the Pacific Ocean. He had, perhaps, but little knowledge of its vastness or its value, but it has been said that his friend, the great naturalist Audubon, who wandered up and down the world searching out its wonders and beauties, had told him many things about the great western country. So he again appealed to Congress for an appropriation to send out an expedition to learn something of the nature and value of their new possessions. The pitiful sum of two thousand five hundred dollars was allowed. Captains Lewis and Clark