Other things are doubtful, but that is certain - some Wellsian political allegory, and even some science

Two more modes or lodes or nodes Wells uses in The First Men in the Moon.  Politics and science.

The novel is not just an excuse for inventing wondrous atmospheric explosions and moon sunrises and so on.  It is also an anti-imperialist allegory.  Not a bad one at that, although Wells makes one really cheap decision.  His moon is, it turns out, abundant with gold.  Sure, why not gold.

"On the other hand, here's gold knocking about like cast iron at home.  If only we can get some of it back, if only we can find our sphere again before they do, and get back, then –“

“Yes?”

“We might put the thing on a sounder footing.  Come back in a bigger sphere with guns.”

“Good Lord!” cried Cavor, as though that was horrible.  (Ch. 18)

Cavor is the scientist, at once narrowly devoted to the cause of knowledge yet in the end much more of a humanist than the narrator who is always wishing for guns.  He wants to conquer the moon people and plunder their resources, an impulse that he feels is entirely natural, while the scientist just wants to study them.  Here we see that  Cavor has joined a Committee for the Abolition of War:

“Sooner or later it must come out, even if other men rediscover it.  And then ... Governments and powers will struggle to get hither, they will fight against one another, and against these moon people; it will only spread warfare and multiply the occasions of war.  In a little while, in a very little while, if I tell my secret, this planet to its deepest galleries will be strewn with human dead.  Other things are doubtful, but that is certain.”  (Ch. 18, italics in original)

It was really the spears that caught my attention, though.  The moon people are a highly advanced, tightly organized society that fights with spears.  The Anglo-Zulu Wars were fought in 1879, not that long before the novel was written.  I suppose there are other relevant colonial conflicts.  I don’t know.

The science – that actual science.  Wells was trained as a biologist.  Jules Verne wanted him to be an engineer, but in The Time Machine and The Island of Doctor Moreau and The War of the Worlds, the scientific principle under investigation is that of Charles Darwin.  In The First Men in the Moon Wells ingeniously prefigures sociobiology.  The moon people are part of a superorganism, an ant colony that has evolved to the point of employing language and advanced technology by means of extreme specialization, each individual “exquisitely adapted to the social need it meets” (Ch. 24).  Wells is the prophet of E. O. Wilson.

These two strands, the political and sociobiological, are combined at the novel’s end, as the scientist fumblingly explains to the big-brained ruler of the moon ants impossible concepts like nations, democracy (“When I had done he ordered cooling sprays upon his brow”, Ch. 25), and war.  However extraneous the satire, Wells does fold it back into the plot in the last few pages.  He is still a novelist more than a reformer at this point.  The scientist becomes the simian snake in the moon ant Eden, destroying their innocence and leading them to commit their first act of war.

The sequel can be found in what must now be hundreds of science fiction novels, stories, and movies.