[The Cañon of the American River, C.P.R.R.]

Carleton Watkins's image of iron rails piercing the wilderness embodies the American notion of Manifest Destiny popular in the 1800s-the idea of the necessity of territorial expansion westward to the Pacific and even beyond. The railroad's development allowed access to remote places; and, as towns and commercial ventures grew up in its wake, the patterns of humans overlaid those of nature.

The aesthetic success of this photograph results from the choice Watkins made when he printed the image, as well as how and when it was composed. To achieve the rich purple-black tones of this print, he exposed the negative for longer than usual and then bathed the print in gold chloride.