Snake River to Station Camp

y 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!

Continuing west on the morning of November 8, the expedition's canoes generally hugged the northern shore of the Columbia's estuary around Grays Bay. That evening they made camp near present-day Portuguese Point. High winds and waves kept them from traveling on the 9th, but on the 10th they continued about 7 miles generally southwest to a small cove about 1 mile northeast of present-day Point Ellice, Washington. Rain, hard winds and billowing waves pinned them to the narrow beach from November 10 and to the afternoon of November 15, eliciting the name Camp Distress for this stopping place. Lewis and a small scouting party set out from Camp Distress on November 13 to explore the area west to the ocean while Clark remained in charge of the camp. In the afternoon of the 15th, after the wind abated, Clark set out with the canoes. Fighting the waves for about one-half a mile, he rounded Point Ellice. He then continued about 2 miles west-northwest to a small sand beach near present-day McGowan, Washington. There, where a small stream ran down from the hills, he made camp. The captains later dubbed it Station Camp.

Table 1. Mouth of the Columbia

he center of the mouth of the Columbia (as projected from the headlands to the north and south of the river’s estuary) on the following maps is shown at the following coordinates:

Map Nicholas King William Clark Lewis and Clark Robert Frazer William Clark Lewis and Clark Present day

Date 1803 1805 1806 1807 1810 1814

Latitude, Longitude 46°15' N, 123°45' W 46°15' N, 123°36' W 46°20' N, 123°36' W 46°50' N, 125°00' W 46°15' N, 124°54' W 46°20' N, 124°54' W 46°15' N, 124°00' W***

Great Circle Initial Azimuth* 088' 089' 072' 311' 271' 278'

Statute Miles** 12.4 19.6 20.5 62.4 42.7 43.1

*Initial heading from the mid-point between Point Adams and Cape Disappointment.
** Great Circle distance from mid-point between Point Adams and Cape Disappointment
*** Coordinates are for the mid-point between Point Adams and Cape Disappoint as shown on U.S. Geological Survey 1:24,000 map; 5.7 miles apart.

Table 2. Celestial Observations Made at Station Camp

louds, fog and rain prevailed over clear skies while the expedition remained at Station Camp. On those few days when weather permitted, however, the captains took celestial observations. These were the last observations they obtained in 1805, and were the only ones they made for longitude on the coast.

The following are the observations that they recorded while at Station Camp November 15 – 24, 1805; all data are from Clark:

Date 16 17 17 24 24 24 24

Type of Observation Meridian altitude of the Sun Equal altitudes of the Sun AM Equal altitudes of the Sun PM Magnetic bearing of the Sun Equal altitudes of the Sun AM Lunar distance from the Sun Lunar distance from star Markab

Number of measurements, Description, Purpose 1 - sun's altitude at its highest daily point in the sky; for latitude 3 - sun's altitude + the time; to check chronometer error 3 - sun's altitude + the time; to check chronometer error 3 - sun's altitude and bearing + the time; for variation of the needle 3 - sun's altitude + the time (incomplete, did not finish the PM part) 10 - angle between the moon and sun + time; for longitude 5 - angle between the moon and Markab + time; for longitude

The results of these observations are discussed in the order given below:

Latitude
Chronometer Error
Longitude
Magnetic Declination - Variation of the Needle

--Robert N. Bergantino, 10/07

1. Refraction has the apparent effect of reducing the earth’s curvature. A common equation for the combined effects of earth’s curvature and refraction, in feet, is: 0.574 x mile. Example: distance 20 miles; 0.574 x 202 = 0.574 x 400 = 230 feet. This means that, at a distance of 20 miles, an object would have to rise at least 230 feet above the eye of the observer to be seen. The inverse of this equation is: = miles to horizon. Example: eye height 5.5 feet; 5.5 ÷ 0.574 = 9.582, take the square root of 9.582 = 3.1 miles. This means that for an observer whose eye is 5.5 feet above the ground the true horizon is 3.1 miles away.

The effect of refraction is dependant principally upon the temperature and density of the air between the object viewed and the observer. An air mass of anomalous temperature or density sometimes can form a lens that will produce a mirage in which objects that are below the horizon appear to be elevated above it. Given the prevalent weather conditions on November 7, 1805 and the distance to the ocean, however, this situation would have been most unlikely.

2. The hills to the north were near Point Ellice, Washington (the highest is more than 1100 feet above sea level); those to the south were just east of Astoria, Oregon (the highest is more than 600 feet above sea level).

Funded in part by a grant from the National Park Service's Challenge-Cost Share Program.