The entries for August 12, 1804 offer an unusually clear window into how a single piece of field data — a 974-yard measurement across the neck of a Missouri River meander — propagated through the journals of the Corps of Discovery. William Clark, Patrick Gass, Joseph Whitehouse, and Charles Floyd all wrote on this Sunday, but only Clark records the surveying operation that produced the figure. The other journals preserve the number, or the bend, or neither, in ways that disclose each narrator’s relationship to the expedition’s officer-class record-keeping.
Clark’s Surveyor’s Logic
Clark’s two parallel drafts for the day are the most expansive, and they alone explain the procedure. While the party halted at noon to take a meridian altitude of the sun, Clark dispatched a man overland:
at 12 we halted in a bend to the left to take the Meridian altitude, & Dine, & Sent one man across where we took Dinner yesterday to Step off the Distance across Isthmus, he made it 974 yards, and the bend around is 18¾ miles
The contrast is striking: a man’s pacing yields a neck less than a thousand yards wide, while the river itself loops nearly nineteen miles to traverse the same ground. Clark embeds this geometric oddity within a richer naturalist’s catalogue — yellow and brown bluffs of clay with embedded sandstone, red cedar on the heights, abundant beaver, and a prairie wolf that "Barkes like a large feste Dog," which he and Lewis went ashore to shoot at without success. He also notes the administrative housekeeping of the day: the appointment of Peter Wiser as cook and provisions superintendent of Sergeant Floyd’s squad.
Gass and Whitehouse: The Number Without the Method
Patrick Gass, the carpenter-turned-sergeant whose journal would become the first published account of the expedition, reproduces the figures faithfully but strips them of their surveying context. Gass writes that the party "went round a bend, of eighteen miles, the neck of which was only 974 yards across." The number is exact; the man sent to step it off has vanished. Gass’s reader encounters the bend as geographic curiosity rather than as the product of deliberate measurement.
Joseph Whitehouse offers an even more compressed version, and his arithmetic suggests he was working from the same shared data pool as the officers:
Sal? 21 Miles from 12 Oclock the 11′? to 12 Oclock this day and Gain? 914 yards on a direct Cource.
Whitehouse’s "914 yards" is almost certainly a transcription slip for the 974 that Clark records, and his framing — distance sailed between successive noon observations versus distance gained on a direct course — shows that he understood the figure as a navigational datum rather than as the width of a particular landform. The bluffs, the cedar, the wolf, the beaver, the mosquitoes that tormented Gass — none of these enter Whitehouse’s terse entry.
Floyd’s Independent Eye
Charles Floyd, who had only weeks left to live, produces the day’s outlier. He records a different wind direction ("a Jentel Brees from North Est" rather than Clark’s south wind), a different distance (16 miles rather than the 18¾ around the bend or Whitehouse’s 21 sailed), and notes "Red Seeder Bluffs on the South Side" — converting Clark’s careful description of cedar-topped clay heights into a single landmark name. Floyd makes no mention of the isthmus measurement at all. His entry reads like the work of a man recording what he himself observed from the boat, rather than copying or paraphrasing data shared at the evening fire.
The day’s four entries thus arrange themselves on a spectrum of dependence on Clark’s officer-record. Whitehouse and Gass both carry forward the 974-yard figure, indicating access to the surveying party’s results, while differing in how much surrounding detail they retain. Floyd, by contrast, writes as an independent observer whose Missouri is shorter, whose wind blows from a different quarter, and whose bluffs are simply named for their cedars. Only Clark — and Clark twice, in his field notes and his journal proper — preserves the full chain from observation to measurement to landscape interpretation, including the prairie wolf whose bark he was the only narrator to hear.
