"… beguiling the tedium of the way by describing to him in detail the various exhibits he had that morning seen at
Merlin's Mechanical Museum. These included such attractions as a juggler, an aerial cavalcade, Merlin's Cave, and a set of Antique Whispering Busts (very ingenious); but these had not interested Felix as much as a hydraulic vase, a band of mechanical music, an mechanical cruising frigate. … he meant next to visit an exhibition at Spring Gardens, where
Maillardet's Automaton was to be seen. This marvel … was a musical lady, who was advertised, rather alarmingly, to perform most of the functions of animal life, and to play sixteen airs upon an organized pianoforte, by the actual pressure of the fingers."
-- Frederica, Georgette Heyer
Felix, a twelve year old boy and one of the minor main characters, is interested in steam power. Over the course of the story, in addition to the above passage, he looks for (but fails to find) one of
Trevithick's railway locomotives called the
Catch-me-who-can, visits a Soho foundry with a pneumatic lift, takes a trip down the river in a steam boat, and rides in a hot-air balloon.
The story itself is set in London, 1818.
As I reread Frederica, it occurs to me that part of what bothers me about steampunk is the apparent lack of any attempt, even, at historical accuracy. I'm sure there are exceptions -- if you want to point me at them, go ahead, but I'm talking about the overall attitude as I've encountered it. ((I still feel that an Edwardian dress without its skirt and with a pair of goggles plopped on is not steampunk but a horribly inaccurate prostitute (an accurate prostitute would wear all the correct undergarments and no dress), and that the peasant blouse + bodice + hiked up floofy skirt combination more properly belongs to the genre of 'halloween gypsy'. Nor do I think that 'vaguely mechanical' or 'has gears on it' necessarily equates to 'steampunk'. I am a steampunk snob, after all: to me, 'steampunk' means 'cyberpunk but with steam,' or 'steam-powered "high tech and low life"'. Watch-part earrings are not steampunk to me; Victorian grunge might be. But that's beside the point.)) I've been told that the fantastical and AU elements of steampunk mean that historical accuracy is irrelevant and/or unnecessary. To be honest, that reminds me a fangirl whining that because the story she just wrote is fanfiction, it doesn't matter that the characters in it are in fact out of character and not at all believable. It also reminds me that good writing that breaks the rules is written by someone who knows the rules and choses to break them deliberately, whereas someone who doesn't know the rules and breaks them accidentally almost always produces crap.
Now, Frederica was definitely not written as steampunk (though some people might retroactively consider it such), but it is historically accurate, from the science to the costumes to the language the characters use. Which, personally, I think is really really cool. It means that Heyer was able to tie in things and people that really existed instead of making stuff up willy-nilly -- and everyone who already knew about John Joseph Merlin or Francis Trevithick gets to have an aha moment and an inside joke with the author, and that makes you feel clever and knowledgeable. Always a good feeling.
Anyway. The thing about steampunk is: steam power is a known science. If it's historical steampunk, then you're dealing with a known period in history. If you're not going to be accurate -- if you're going to break from what's known, break the rules -- then it should be a deliberate choice, not an accident. Otherwise you may find yourself doing the equivalent of trying to convince people that you can propel a metal wagon in which you're sitting by holding a magnet out in front of it, or that the Aztecs really came from Mars. 'Alternate universe', 'fantasy' -- hell, even 'fiction' -- those are no excuse to be lazy.