The Floating Palace was an amphitheater constructed on a barge in Cincinnati, Ohio, at a cost of $42,000. It had a standard size 42 ft circus ring, a seating capacity of 2400, and was decorated with carved woodwork, mirrors, velvet hangings, and thick carpets. 200 gas jets lighted the palace, and the steam engine on a towboat furnished heat. The towboat also held a menagerie.
Spalding and Rogers Floating Palace opened in Pittsburgh in March 1852, and was an all year attraction that annually toured the Ohio and Mississippi Rivers and spent winters in New Orleans.
In 1857 Gilbert R. Spalding and Charles J. Rogers opened the "Spalding & Rogers Railroad Circus" on nine custom-built cars. Their tour started in Washington D.C. and traveled through the states of Pennsylvania, New, Massachusetts, Maine, the British provinces, Michigan, and Ohio. In Ohio they continued their tour along the river on the Spalding and Rogers Floating Palace.
PHOTO: Wood engraving in Gleason's Pictorial Drawing-Room Companion, Feb. 19, 1853.
Source: http://www.americanantiquities.com/articles/article%2011.html