Today I discovered Focke's set of 1873 emigration documents from Germany. Not his passenger list when he left, but instead local documents related to his departure from Europe. For some reason, I avoided using these records as I "had it in my head" that they only started in the mid-1880s. That was a mistake.
It's been a long time since I have gotten excited about finding a record, but this one was a great find.
Focke's age is clearly stated on the partial copy of the record used as an illustration on this blog post. It also indicated his name and provides his 12 January 1857 date of birth in Wrisse.
And it states he's headed to America.
There's more in this permission to immigrate--including a letter signed by Focke's father. My feeble attempts to read German so far indicate that it mentions Focke's sister who was already in the United States.