By noon, October 18, 1805, Meriwether Lewis had completed his celestial observations, and William Clark had measured the width of the Snake and Columbia Rivers. Lewis then completed recording a vocabulary of primal words in the local languages. This done, the expedition launched its canoes and headed downstream on the Columbia River. Two hundred river miles—and several portages—brought them to Pacific tidewater near Beacon Rock on November 2.
Five days later, November 7, the party reached a rock 20 feet in diameter rising more than 50 feet above the river level; it stood about one-half mile from the river's north shore. From an unspecified location near this pillar of rock, William Clark focused his gaze downstream to the west along the course of the Columbia River. What he saw there prompted him to record: "Great joy in camp we are in View of the Ocian." Strangely, Clark's journal is the only one to express this joy. Ordway, on November 8, simply records: "we can See along distance ahead we expect we can see the mo. Of the Columbia River . . . but it appears a long distance off."
Clark's journal entry has engendered considerable discussion. What did he see that prompted this entry? Although this was not a celestial observation, it merits treatment here.
Clark did not see the Pacific Ocean—its eastern shore lies about 20 miles west of Pillar Rock. Because of the earth's curvature,1 the horizon that Clark would have seen from near Pillar Rock (assuming that he was standing up and looking west) would have been only about 3 miles distant; that is, just southeast of Grays Bay. In order to have seen the ocean, itself, Clark would have needed to climb the rain-soaked hills on the mainland north of Pillar Rock, ascending them to a height of about 230 feet above the river—that is, he might have seen the ocean provided that the fog had lifted by then and the rain had stopped. Nevertheless, the geographic setting of the expedition's route for the latter part of November 7 provides some clues to what Clark saw or thought he saw. About 5 miles upstream (eastward) from Pillar Rock the Columbia River, in its seaward course, makes an abrupt bend from northwest (azimuth 325°) to just south of west (azimuth 260°). This bend marks the upstream end of the river's estuary and, from that point, the Pacific Ocean lies about 32 miles to the west. Hills.2 border the north and south sides of the estuary. As seen from Pillar Rock, however, the hills that are near the north and south ends of the present-day Astoria Bridge hide those hills that are farther west. And, as seen from near Pillar Rock this effect creates a 4-mile-wide span of true horizon. This 4-mile-wide span of horizon may have suggested to Clark that he was seeing the ocean . . . or at least, the direct opening to it. Therefore, although the ocean—the expedition's long-sought goal—still lay unseen below the horizon from near Pillar Rock, Clark's sixth sense of geography must have told him there was open water all the way to it. Joy indeed . . . though short lived!