Whoops, I mixed up Mankiw’s Principles of Microeconomics and Cline (or Cechetti’s) Money, Banking and Financial Markets.
The 19th century source is Bagehot. But that won’t make sense without the above fundamentals. (Bernanke’s work on the Great Depression is also a good empirical study on deflation. But again, not worth tackling until after one of the Money & Bankings.)
And unless I have the wrong Mankiw, that doesn't look like a 19th century book.
[0] https://scholar.harvard.edu/mankiw/publications?page=3