Chapter 1: Section 6: Page 47: Line 48 (841)

 One night when it seemed Franz Ferdinand had dropped off the map of greater Chicago, Khäutsch got on the telephone and began calling around town, eventually reaching White City Investigations.

* * * * * * * * * *

It's sometimes difficult to follow Pynchon's narrative, at least in a linear manner. So far, Against the Day is easier to follow than Gravity's Rainbow because it has, so far, confined itself to reality (or near enough to reality). Without warning, Gravity's Rainbow would skew into somebody's fantasy or dream or the narrative would sidestep through time or be taken over by an outside perspective of the book as seen through some other medium, like a musical or comic book or news reel. Then you'd have to re-read that section two or three times to figure it out. I imagine some people, being against re-reading the same book they're currently reading, just powered through until they felt they understood it again. Maybe that's a good recommendation to feel you've gotten a foothold on the narrative but I'm completely against it. Don't move on until you feel you've got a grasp on what just happened! Except that bit where Slothrop climbs into the toilet and winds up in some world where there's only one of everything and some cowboy with his sidekick. That was weird.

What I'm getting at is that this line feels like Max is remembering how he came to be dealing with White City Investigations even though it just pops up as if it's a recent story that goes along with Max's revelation of being too clever to keep an eye on the stupid Archduke. This just seems like the beginning of the origin story of how Max and Lew began working together. Although that theory will probably get blown apart by the next line where Lew covers the call to Max and we already know that Lew learned about the Archduke job when he was given the Austro-Hungarian dossier.
    What this sentence reveals, I think, is Max's hesitancy to admit that he's failed at his only job. Only after he realizes that he's getting nowhere, he calls up his "opposite number" at White City Investigations in the hopes that his familiarity with Chicago will get the job done.