Milk first or milk secondis a perennial issue in the tea-drinking world.
In all the years since the OP was posted I’m the first to ask about the “several flavors of phosphates” on the menu?
Ask what?
Huh well you learn something every day.
This link gives a 1918 recipe and it seems to indicate that “Boston style coffee” is made with an egg. Seems to make more sense than just “extra cream” since the diner charged twice as much for it.
http://www.metaphoriclabs.com/articles/boston-coffee-recipes/
Interesting and with that I found this recipe for roasting your own beans from Mrs. Lincoln’s Boston Cook Book in which egg is added to the coffee “for clearing.” It has a recipe for adding the egg when roasting the beans where this is “the cheapest form in which to use egg for clearing” but also for adding the egg (and shell) when boiling the coffee (“or the whole egg may be beaten with the ground coffee, and such portin of it used as is needed, keeping the remainder closely covered”).
And there’s this paragraph from Steinbeck’s Travels with Charley:
Though this page suggest it was primarily just a way to settle grounds out of boiled coffee, which doesn’t seem like something you’d pay extra for.
My Dad was a short-order cook in the early 1940’s… and as I grew up, I often heard him refer to (and order his coffee) as "Boston-style. So, to answer your question:
“Boston” style coffee means lots of extra cream… double or triple the usual amount… which also accounts for the extra cost in the 1930’s. It was generally taken with sugar as well.
PS: Definitely NOT served with an egg in it !
It’s coffee that plays wicked hahd when it goes to the pahk.