My great-great-great-grandmother's brother, David Downie, was a missionary to India. On ancestry.com I found a link to a passport application he made to return to the United States. It's an interesting glimpse into his life.
He was born in Glasgow, Scotland 29 July 1838. He emigrated to the U.S. in June 1852, residing in various places in the U.S. until 1873. He became a U.S. citizen in 1857. From 1873 on he was a missionary in India.
This is a 1918 request for an emergency passport so he can travel back to the U.S. It's interesting that it gives his destinations en route as the Straits Settlement in Ceylon, then Hong Kong, Japan, Canada, and then the U.S.
David Downie died nine years later 19 July 1927 in Pasadena, CA, at the age of 90. His wife was Annie Hershey. While I think she was perhaps from Pennsylvania, I could not determine whether she was related to the Hershey of Hershey's chocolate or not, but I also didn't spend much time looking.