Or, as the author of this book, one might say "Ha ha! I will do both at the same time! Mua ha ha ha!"
(The "mua ha ha" is not attested, but I am morally certain that's how he said it.)
The chapters flip back and forth between 2132 and alt-1779. On one side, inexplicable marsquakes threaten the mining operation; a gritty but slightly career-shadowed lieutenant attempts to investigate. On the flip side, the HMS Daedalus catches wind of alchemical pirates off Mercury, and (a different) lieutenant draws extra duty in the chase.
This is amusing -- and it would make a flashy TV miniseries -- but there's not all that much to it. The characters are all pretty much what you see on the surface; they do their thing and good triumphs. With sequel hook. Yay. A couple of charactery twists appear and are quickly disposed of. Also, the author isn't quite as hard-science as he thinks he is. (The dialogue has that overexplained tone that means the writer has just read a lot of articles. Also: "ionizing radiation", not "ionized".)
The alternate history pulls the cameo gag. Ben Franklin, the learned alchemist of the rebellious colonies on Ganymede, would have been enough. Throwing in Benedict Arnold, John Jay, Horatio "Hang-a-Lantern-On-It" Nelson, and a couple of spoilery other historical figures is too much.
There's probably something to say about the planetary romance trope, which is even more blatantly colonial here than in Burroughs. It's leavened by the lurking presence of the Saturnite race, who are as far ahead of 1700s humanity as humanity is ahead of the poor primitive Venusians, but the Saturn folks are isolationist (a Prime Directive?) and so the tables aren't really turned. And then the author falls into the erase-the-American-continent trap, which I suppose closes the topic for anybody who was interested in the first place.
It's a fun read. It's neither outstanding or broken. That's about all I can say.
(Yes, I picked this book up because I'm working on an age-of-alchemical-sail-in-space game. Fortunately the author has a completely different take on it than me. I would have been tempted to steal his moons-of-Jupiter gimmick if I'd seen it a couple of years ago, Ah well, my design is long since nailed down...)