"Polka Jacket Trimmed with Imitation Ermine" (1856)

The term "polka jacket" is rarely defined in period sources, but derives not from the dance but from the military jacket of the same name.

The General Regulations for the Military Forces of the State of New York (1870) describes their version, one of the two "Uniform Coat[s] for the Non-Commissioned Officers, Musicians and Privates of the National Guard Infantry" as "differing from the chasseur jacket [described meticulously in the article's previous paragraph], in being without skirt, but extending without seam five inches below the hip; without opening or buttons behind, and round edge in front" (p.252).  Women's knitted polka jackets seem to be fairly consistent in their details -- a single-breasted close-fitting jacket, usually collarless, with long sleeves and smooth skirt with rounded fronts, often trimmed, as this one is, in faux ermine, and apparently always worked in brioche stitch, possibly because brioche's inherent stretchiness made it easier to fit smoothly.

Here is the full pattern from the January-June 1856 issue of "Godey's Lady's Magazine" --

 A similar polka jacket from an 1849 issue of "Family Friend" was transcribed by Carol Rhodes and appears in modern-pattern format in Helen Bonney's article in the January/February 2013 issue of "PieceWork" magazine.