"How does your world do it?"

"Married people are just supposed to not have sex with anyone else ever, in most places. This probably causes problems when one spouse loses their sex drive completely and the other one doesn't, but I don't know if it's more or less total heartbreak and sexually transmitted diseases than your way. There are also people who don't care if their spouses have casual sex or date other people but most people do care and can't choose to stop."

"I bet we have more venereal disease. I can't imagine a system where more people wind up getting the clap."

Bruce puts a couple of pieces together, including the meaning of "in a family way". "Wait, does your world not have condoms? I should definitely invent condoms." 

"Condoms exist but people don't really like using them."

"You'd think they'd dislike getting the clap even more. But that's people for you."

"Well, I mean, you have to clean the condom after you use it, and that's a pain."

"Oh, I see--we have one-use disposable ones but I guess they're more expensive to manufacture here. I don't know if I can reinvent the disposable condom but I might be able to reinvent some stuff that speeds up manufacturing in general."

"Huh. ...seems like the real limiting factor would be number of sheep."

Yup, just as he's suspected. Another reason not to try to have sex any time soon.

"Well, that's why the disposable one is its own invention--there's a way to make them out of latex which I think is made of a kind of tree sap, but I don't know how to identify the tree or how to get from the tree sap to something with the right shape and texture."

"We should probably figure out the simplest things you understand well enough to explain. --Actually, our first step should be you writing up as complete a history of your world as you can manage. --Actually, our first step should be figuring out a way to prove you're not a fake. Not everyone made up a language as a child, even in the Imperial Society."

"Yeah, I should definitely write down everything I remember before I forget any of it. Proving I'm not a fake . . . my phone doesn't have much battery left, but I guess I could let people disassemble it and see that it couldn't have been made with current technology? We'd want to find someone who's word would be really convincing to do that, though, since I only have the one. Alternately we could try to make a couple simple things with practical applications and then ideally it wouldn't matter where I was from since I would have already demonstrated I have useful ideas."

"I wouldn't want people to not know that interworld travel is possible! --I will send a letter to Cavendish and have him report at the next Imperial Society meeting."

"That's true, people might be able to replicate it someday! Maybe while you do that I should get a pencil--or a pen if I need to invent the pencil--and paper and start writing down a giant pile of notes. It'll probably take me a while, especially getting it into some sort of useful order."

"We have pencils!"

Eli rings a bell which fetches a servant. "Paper and pencils for-- I'm not actually sure I caught your name--"

"Bruce Banner. Sorry, I always forget to say."

"For Banner, thank you. And bring us our dinner here, I think I'm going forget to eat again. And if Claire hasn't told someone to do it, make up a bed for Banner please, he'll be staying here indefinitely."

That sounds like everything. "Thanks." 

And when the pencils and paper arrive Bruce can dive headfirst into writing down everything he can remember thinking about before a couple days ago, starting with the big bang and proceeding from there.

And Eli starts writing a letter to Cavendish!

Bruce's entire knowledge of the world is going to take many hours and many sheets of paper to write down. It has topic headings like "chronological summary" and "biology (theory)" and "biology (practical) and "biology (list of species)" and "physics (equations)" and "physics (practical)" and "chemistry" and "governments" and "biology (human physiology)" and "food" and "music" and "math (pure)" and "math (applied)" and "religion" and "biology (misc)" and several dozen other things. Also if he sleeps or has a conversation while writing it he might Lose His Place. Hopefully Maturin is okay with having a paper-munching robot in his library; if not he will probably respond to a sharp poke in the head.

Eli is going to remove the papers and read them once he's done and take notes.

Hopefully Clarissa doesn't mind having two paper-munching robots in her library.

No, that's pretty much what she expected.

And eventually, at some hour of the day or night: "I think tha'ss everyth . . ." thunk. Now he is insensate on top of the desk with his right arm wrapped around his head and his left hand dangling next to him like a mistreated grapefruit.

Unfortunately, Eli had fallen asleep on his papers two hours ago and could not do anything about this.

In the morning Clarissa finds them.

"...I can't believe someone thought Banner was a sub."