Once I understood where they came from, I could then track the history of that larger group, their arrival from Prussia and how they got to Prussia, knowing that even if I couldn't track the individuals, I had high confidence that a large number of the people being described were my ancestors because the community was so insular over such a long period of time. I could associate certain surnames with certain divisions within the Mennonites and track those groups, even when I couldn't trace with any certainty the individuals I was directly descended from versus their siblings and so forth.
However, history is populated by the ordinary as well as the distinctive. Google books can somewhat randomly help find biographical information about disctinctively named and/or particularly noteworthy individuals, which is fun. But I recently decided to attempt to apply to my recent Frisian immigrants what I had been doing for a while to my Mennonite migrations.
With that in mind, I went back to Hein's passenger record. He is on the top of a page in the middle of the list and on the line below him is a young man named Jan Visser whose birthplace is listed as Achlum and whose father is listed as still living there. I've tried to find Jan Visser (or his father, whose first initial is supplied) in the civil registry but so far to no avail (this is not as surprising as it might seem; Jan Visser is a profoundly common Dutch name).
I looked further down the page, noticing that some surnames were familiar, but they were common ones which I had noticed in the past. In the intervening months since I had last looked at the page, however, I'd spent a lot of hours deciphering village names and identifying them on maps. This time, I didn't see a lot of Dutch names from a lot of difficult to decipher towns and villages. I saw a lot of Frisian names from a lot of Frisian villages, many familiar from my tree, and many others familiar because they weren't that far from villages in my tree.
How many Frisian immigrants to the United States had there been?
When I first went to visit my family in the Netherlands, I stayed at a hostel in Amsterdam and asked the kind people at the front desk to go over my planned train journey to Veenwouden (which I now know to be on the wrong side of Leeuwarden from all the now familiar ancestral villages) to make sure I hadn't screwed up. Their initial reaction was surprise: that's a place people leave, not a place people go to. I'd spent years assuming they meant, people leave small towns like Veenwouden to go to big cities like Amsterdam, just like so many communities emptied out in the late nineteenth and early twentieth centuries as part of urbanization.
Turns out they might not have just meant that.
Here's the list of communities (last residence) from the page in the passenger list that starts with my great-uncle:
Achlum (2 lines) (Friesland)
Oenkerk (3 lines) (Friesland)
Schingen (2 lines) (Friesland)
Usguerd (modern name is Usguert and it's in Groningen)
Almelo (3 lines) (Overijssel)
Haren (the one in Groningen, surely, since the contact is an uncle living in Groningen)
Minnertsga (2 lines)(Hein's brother Sjoerd married a woman from this town)
Goenga (with an umlaut over the e) (Friesland)
Berlikum (2 lines) (Friesland)
Oajeuniski (Russia) (3 lines)
Groningen (2 lines)
Uithuizen (like Usguert above, in Groningen, combined into something called Hefshuizen which was then name changed to Eemsmond)
Over a third of the page is from Friesland (13 out of 30 lines). Groningen is the next province east and that accounts for another 5 lines (bringing us to 18 out of 30). The guy in Plymouth, USA I'm having a lot of trouble making out the contact address for his uncle, but the guy's name is Jacob Tolsma and his uncle is Ch. Postma, and I don't know if it is possible to come up with more distinctively Frisian surnames than those. Which brings me to 2/3rds of the page.
I don't want to oversell this. I'm by no means suggesting that most of the passengers on this boat were Frisian. But this is a bigger batch than I expected and the group sizes are small (some singletons and no big families).
How many of the people who left Friesland went to the US?
What I wanted was a historical atlas of Friesland, showing population patterns, or possibly a historical atlas of the Netherlands, with times series for each province so you could see patterns of population growth and movement. _That_ was going to be asking a lot (and I did realize if I could find it at all, it probably wouldn't be in English). I did stumble across some really amazing stuff about historical atlases that may or may not turn out to be useful, but wouldn't help with this particular problem.
What I _found_ was _Frisians to America 1880-1914: with the Baggage of the Fatherland_ by Annemieke Galema, which almost certainly won't have any information about my grandfather and great-uncle and my great-uncle's friend Jan, but may be able to let me trace more distant relatives who drop out of the civil registry, not because they died too recently to be in genlias/allefriezen, but because they got on a boat and came to the United States.
A detailed review can be found here:
I also picked up some other books about Friesland (research isn't an art or a science: it's a reflex) while I was at it. If they turn out to be useful, I'll mention them later.