Garrett Serviss' Edison's Conquest of Mars (1898) is the sequel to a knock-off. Following the success of War of the Worlds, the Boston Evening Post ran an unauthorised variant called Fighters from Mars (author unknown, but credited to, I kid you not, "H.C. Wells"). Conquest is the sequel - a serialised novel in which, under the championship of Thomas Edison, Earth strikes back.
Conquest has certain merits as a part of science fictional history: it is a classic Edisonade and it is an early transformative work. However, it is particularly remarkable in how it displays the worst traits of both genres.
An "Edisonade" (term defined by John Clute) is a type of proto-SF based around an inventor and his (invariably a man) works. Everything from Tom Swift to Herbert Strang to "The Steam Man of the Prairies" (which is kind of awful as well, actually). In this case, the term is literal, as Edison - shown here as a scientific, moral and political paragon - invents, well, pretty much everything: spaceships, spacesuits, disintegration rays, asteroid mining, you name it...
That would be fun if the book weren't so terribly, terribly goofy. All the nations of Earth gather together (stereotypes on full display) and build a massive space armada. This is done by pledging all of the world's money and all of its industrial output. The Earthling then head to the Moon as a test run, and find that it is composed of diamonds (which is handy - the mission has already turned a tidy profit and/or crashed the world economy). The fleet meanders by an asteroid (Made of gold! Space is awesome! Economics less so!) and eventually engages the Martians on their homeworld. The battle goes to and fro, but eventually a (beautiful) (princess) human servant on the planet informs Edison of the ONE LEVER THAT WILL DESTROY THE ENTIRE PLANET. Edison et. al. storm the unguarded lever-building, pull the lever and watch all the Martians die. The humans head home triumphant, having taught the Martians a thing or two about genocide.