Garrett P. Serviss’ 1898 Edison’s Conquest of Mars is a sequel to 1897’s Fighters from Mars, or The War of the Worlds in and near Boston, which was a version of H. G. Wells’ The War of the Worlds rewritten and dumbed down by persons unknown in order to better suit Yankee sensibilities.
Having survived Mars’ first attack thanks to the Martian vulnerability to modern Terrestrial diseases, the people of Earth are alarmed when astronomers report that the foul Martians are preparing for a second foray. Mars has the technological edge; it is likely that they will be able to guard their second invasion force against disease.
Is Earth doomed? No. Earth has Thomas Edison.