OK, almost by accident we seem to have decided to start a new forum game where we describe where we're stuck in a game or just where we are generally or even just a general overview of the game's setting and peculiarities and you guys have to guess what game it is, the correct guesser gets to set the next game to guess!

Depending on how hard this turns out to be it might be an idea to keep this to games on GOG (or have been on GOG, in the past, at least) - this one is currently on GOG at least:

OK I'm snooping around the chateau / fortress of the grand master of the BSORC, his dead body is laid out on a slab in one room while the next room is like a library-come-laboratory with books, and a sciencey area with a bunsen burner and jars of chemicals

There seems to be a puzzle involving these chemicals, measuring spoons and a series of 'magic number' squares positioned around the room

- what game is it?™

Nope, it is neither of those

Could it be Amnesia?

*edit to add: And by the way, this is fun!

Nope not Amnesia

That was my next guess. I'm guessing someone is going to see the clue about the Master's society and know it right away. I'm sitting here forming random word strings that are "arcane-y" sounding trying to guess it myself ;)

This will be fun. Sounds a little familiar but right now - no clue.

Nope its not a Dracula game either

Post Mortem (based on BSORC and Google)

nevermind LOL

yep - The Brotherhood of the Secret Order of the Rosey Cross (croix?)
Somehow, I'm an American, in Paris investigating a murder for a girl with black, bobbed hair that started off normal but has gone off in some weird Dan Brown direction involving the Knights Templar and it's NOT Broken Sword!

Post Mortem it is - your go!

I'm wearing a dress with a bustle, and standing amidst the wreck of an airship.

(Hey, I'm at work, don't have time to think of something difficult.)

Arcanum?