Nicely documented. Money can say a lot about culture. I had unusual bills ( e.g., U.S. 10 dollar gold certificate, various silver certificates) from when I delivered newspaper as a kid, and unfortunately spent most of them on Mad Magazines and D.C. comic books. However I saved a $1 bill from 1935 that did not have "In God We Trust" on the back. Apparently they later added the saying that as a political device shortly after the mid-1930's. It's physical evidence that the earlier U.S. was not as beholden to religion as it has become today.