Conversation so far:
When did Thomas Eakins' career begin?
Thomas Eakins career began in the early 1870s
How old was Thomas Eakins when his career began?
Thomas Eakins career began in the early 1870s
What was a name of one of Thomas Eakins' first works?
One of Thomas Eakins' first and most famous works is Max Schmitt in a Single Scull

Question: What kind of materials did he use?
Self-contained rewrite: What kind of materials did Thomas Eakins use?