No. 186. Chicago, Burlington & Northern Rail Road Bridge Across Mouth of La Croix River

Art Historical Context

In 1891, Henry P. Bosse captured *No. 186. Chicago, Burlington & Rail Road Bridge Across Mouth La Croix River*, a cyanotype documenting one of America's engineering feats during the Gilded Age. This photograph depicts the ambitious railroad bridge spanning the remote mouth of the La Croix River—likely in the rugged borderlands of Minnesota and Wisconsin—built by the Chicago, Burlington & Northern Rail Road. At a time of explosive westward expansion, such structures symbolized the nation's industrial might, connecting remote frontiers to booming markets and facilitating the transport of timber, iron, and passengers. Bosse's choice of cyanotype, a pioneering 19th-century photographic process using ferric ammonium citrate and potassium ferricyanide, produced the image's iconic Prussian blue tones on a 14½ × 17⅜-inch sheet. Affordable and light-sensitive, cyanotypes were ideal for engineers like Bosse to reproduce detailed technical views quickly, yet their ethereal blue hues lend an artistic poetry to utilitarian subjects. Today, housed in the Metropolitan Museum of Art's Photographs Department (gift of Charles Wehrenberg and Sally Larsen, 2014), this work offers a window into the interplay of technology and wilderness, highlighting how photography preserved vanishing feats of the railroad era.