Sentence:  Among the large collection of historic criminal daguerreotypes, tintypes, and ambrotypes on display was that of Louis Degurie, who was one of the first to use photography to make counterfeit "<WSD>brownbacks</WSD>," in 1862. 
Meaning of the word marked with <WSD> tags:  A note of scrip printed on brown paper, such as that issued by the city of St. Louis during a financial crisis.