19th Century New England
New Jerusalem, 1888
Will Henry and Dr. Warthrop live in the sleepy town of New Jerusalem, which is apparently somewhere in New England. Now, if you were to Google New Jerusalem you wouldn't get a place on the map. That town doesn't actually exist—at least right now. But one thing that will pop up is the fact that New Jerusalem comes from a biblical passage describing the heaven on earth that God creates as a reward for the faithful and righteous.
Do we think that Yancey named his fictional town after heaven on earth because it's so pleasant there? Not really. What kind of heaven includes vicious, mindless, man-eating creatures waiting to snatch you from your bed? Do we think that Will Henry made up the name of the town as a pseudonym because his experiences there were so divine? Nah, we don't really think that's it either. Will Henry wasn't exactly blissed out about his life with Dr. Warthrop, and he says himself that he isn't all that religious:
My father had not been a particularly religious man; aspects of the divine he had entrusted to my mother's care. She had prayed with me every night and had taken me to church every Sunday, to instill a bit piety in me, but I had inherited my father's indifference to religion and had gone through the motions of devotion without much conviction. (12.202)
Most likely, though, is the option that Yancey is well versed in New England history, and thus knows it was founded by Puritans. They were pretty big into the New Testament and the idea that if you lived your life adhering to it's strict rules then you would receive your reward in the afterlife. Sounds like a group who'd be pretty likely to name a town New Jerusalem, don't you think?
So what we have now is a town that very well could exist in New England. It has a likely name, and Dedham and Swampscott (the only two other places that are mentioned during the course of our tale) are definitely very real places in Massachusetts.
Since we know that Dedham is a three hour carriage ride from New Jerusalem (because Dr. Warthrop and Will Henry make the trip several times) we can assume out that New Jerusalem isn't located too far from there.
This is a very clever ploy by Yancey. He has given his story a location that could have existed, without rooting it in a place that very definitely does. This allows him to sculpt the story in such a way that makes the tale very believable—and harder to prove untrue. It's the same trick he uses with the exotic parasites he mentions; several of them really do exist (including the terrifying one that swims up a stream of urine into your unmentionables only to release painful barbs locking it in place), and then he weaves in B. arawakus, which as far as we know doesn't exist… but it could, right?
425 Harrington Lane
The distinctive mansion in which Dr. Warthrop and Will Henry reside also helps set the tone of our story. The house on Harrington Lane—which is infamous in New Jerusalem for having strange visitors and bizarre goings-on—is consistently described as being dark and gloomy and just slightly dilapidated from a lack of TLC:
When the dust and dirt became intolerable, about every three months or so, he would press a rag and a bucket into my hands and tell me to "snap to" before the tide of filth overwhelmed us.
So the doc and Will Henry aren't much for housekeeping. But their lack of tidiness conjures up images of clutter and disarray that lend themselves to a kind of claustrophobic atmosphere. On top of that, much of what occurs takes place either in the basement or Will Henry's little loft, which only adds to the general feeling of being cramped.
The basement is like any other basement—dark, a bit damp, and cold, which is perfect for preserving Dr. Warthrop's various specimens. It is where the doc keeps his laboratory full of grotesque detritus and science-y paraphernalia, so we picture it looking a bit like Dr. Frankenstein's lab.
All of this helps to contribute to fashioning an image in our minds that is like a cross between the Addams Family mansion and the MST3K lab, which is pretty perfect when you're trying to tell a really spooky story.