La Galopade is a short, simple sequence dance created by French dancing master, choreographer, and author Eugène Giraudet and preserved in the enormous 55th edition of his dance manual, La danse, la tenue, le maintien, l'hygiène & l'éducation (c1900) as well as in his 1913 Méthode moderne pour bien apprendre la danse. A matching description appears in George Washington Lopp's La Danse (Paris, 1903).
In the companion volume to La danse, Traité de la danse (c1900), Giraudet dates the dance to 1889; its earliest appearance may have been on the accompanying sheet music by composer Félix Chaudoir.
The dance itself is consistent across the sources and entirely straightforward to reconstruct. The dancers start side by side, as shown above (click to enlarge), inside hands held high, gentleman's left hand on his hip (palm out) and lady's right hand holding her gown. They start on "outside" feet (his left, her right). Couple follows couple around the room in a line or circle.
Because it moves against line of dance, La Galopade is best done by the room as a whole, rather than as a variation in a normal galop or polka.
La Galopade (16 measures)
2b Polka forward, side by side
1b Polka in place, turning half round individually to face against line of dance, changing hands
2b Polka forward, side by side, against line of dance
1b Polka in place, turning half round individually and coming together in normal closed hold
2b One bar of galop and one bar of polka (= four-slide galop); half-turn
6b Repeat galop/polka (four-slide galop) sequence three more times; one and a half turns
2b Polka; one complete turn
Open to original position holding inside hands and restart from the beginning.