This section is from the "A Complete Dictionary of Dry Goods" book, by George S. Cole. Also available from Amazon: A complete dictionary of dry goods and history of silk, cotton, linen, wool and other fibrous substances,: Including a full explanation of the modern processes ... together with various useful tables.
Down. The fine, soft covering of fowls under the feathers, particularly that of swans, ducks, geese, and other water-fowls. Down-feathers are characterized by a downy structure throughout. They more or less completely cover the body of the fowl, but are always hidden beneath the contour feathers, and serve as a sort of padding about the bases of the latter. The eider duck yields most of the down of commerce. [See Eiderdown]