It's fairly frequently that we don't use or mention something that is historically in-period for Fallen London because players would think it's anachronistic. Examples of such things include semi-automatic pistols (definitely a thing you could buy in Europe in 1899). There's one bit in FL where you run into a saxophonist and the only reason that flies is because he's a Devil, and Devils in the FL setting are culturally unstuck in time (even though saxophones had existed for a long time in the period). This phenomenon is a byproduct of the simplified and often incorrect way people conceptualize history.
But one thing that falls under this rule that I am often sad I can't use is the word 'dude' (first attested in English in 1877).
And you might say "well if you know you're right and it is period appropriate why not just do it" and the reality is that it doesn't matter that it's ackshually correct if it's still going to knock the median player out of the story.
Also when something like this happens (sometimes we misjudge what people think is Victorian) we get emails and nothing hurts the soul more than getting an email where someone confidently and wrongly tells you that you've made a mistake (the most common cause of such emails is actually obscure or unusual word usage or grammar).