Conversation so far:
What was Harry Hopkins social work?
In 1915, New York City Mayor John Purroy Mitchel appointed Harry Hopkins executive secretary of the Bureau of Child Welfare which administered pensions to mothers with dependent children.
When did Harry Hopkins start his position as Executive Secretary of New York City Bureau of Child Welfare?
In 1915, New York City Mayor John Purroy Mitchel appointed Harry Hopkins executive secretary of the Bureau of Child Welfare which administered pensions to mothers with dependent children.

Question: where did he do his public health work?
Self-contained rewrite: Where did Harry Hopkins do his public Health work?