1834
Mint ratio moves
Congress changes the gold content of the eagle. The mint ratio moves from 15 to 1 toward roughly 16 to 1.

In 1834 Congress reduced the gold content of the eagle. The official mint ratio moved from the 1792 relationship of 15 to 1 toward roughly 16 to 1, a gold-friendlier standard.
The law could change the ratio. It did not decide which metal the market would keep. The Second Bank’s charter is still alive until 1836.