Conversation so far:
What was some political activities that Robert Dale Owen partook in?
During the American Civil War, Owen served in the Ordnance Commission to supply the Union army.
What did they supply the union with?
In 1862 Owen wrote a series of open letters to U.S.
government officials, including President Abraham Lincoln and U.S.
Secretary of the Treasury Salmon P.
Chase.

Question: What were these letter include?
Self-contained rewrite: What were the open letters to U.S. government officials letter include?