Nicholas Biddle, the editor of the first published Lewis and Clark journals (1814), simply paraphrased Lewis: "The Indian woman had just time to grasp her child, before the net [italics added] in which it lay at her feet was carried down the current." Biddle, of course, had talked about the incident with Clark.
Elliott Coues, in his 1893 edition of Biddle's work, led his own readers astray by confusing two different words having two different roots.
This is an interesting use of the old word bier, which we found early in this work employed for a covering for the head to keep off mosquitoes (whence our mosquito-bar); but it is now archaic, except in connection with funerals. The "net" of the text therefore is simply the child's cradle, made light and portable, something like a basket.1
Nine years later Reuben Thwaites allowed that Coues might have been right, but cited an early 18th-century traveler's use of a canvas sack as a baire against mosquitoes while on the lower Mississippi River, and wound up implying that baire and bier were synonyms.
The term baire, thus used, would readily spread, among the French voyageurs and traders, throughout the entire Northwestern region; and by the time of Lewis and Clark the canvas was, at least sometimes, replaced by gauze or net (as affording fresh air).2
The recent Dictionary of American Regional English confirms Thwaites's conjecture. Four variants—bier, baire, bear, and bére—are linked to the Cajun word boire, and in turn to the French barre, meaning cross-bar, with each word denoting a "mosquito bar." All were common in Louisiana in the late 18th century.3
Regrettably, the up-to-date Merriam-Webster's compounds a century's-worth of confusion in its opening definition of bier: "archaic: a framework for carrying." Even the venerable Samuel Johnson, the 18th-century British father of modern English dictionaries, wasn't that archaic; he specified the condition of the burden: "on which the dead are carried to the grave."4
1. Elliott Coues, ed., History of the Expedition under the Command of Lewis and Clark . . . 1893. (Reprint, 3 vols. New York: Dover Publications, 1965), 2:395.
2. Reuben Gold Thwaites, ed., Original Journals of the Lewis and Clark Expedition, 1804≠1806 (8 vols., New York: Dodd, Mead, 1904-5), 2:197-98n.
3. Frederic G. Cassidy, ed., Dictionary of American Regional English (3 vols. to date, Cambridge: Harvard University Press, 1985–1996), s.v. bar.
4. Samuel Johnson, A Dictionary of the English Language: in which the Words are deduced from their Originals . . . (2 vols., London, 1755), s.v. bier.