The Time Traveller flies into the future with a greater velocity than before. Although he is travelling thousands of years per second, he begins to notice day and night again. The sun grows larger and redder. Finally, it seems that the earth has stopped rotating, and is circling the dying sun as the moon used to circle the earth.
When he brings the machine to a stop, he finds himself on a sloping beach. Vegetation covers every surface facing the unmoving sun; the air is very thin. Behind him he sees a huge white butterfly in the distance, and slowly a red rock begins to move toward him. It turns out to be a giant crab. While he is staring at it, he feels something brush his neck. It is the antenna of a second giant crab, right next to him. He hurriedly skips a month into the future to escape, but finds the beach covered with more crabs. He goes on, stopping every hundred years or so, watching the "old earth ebb away." Finally, thirty million years into the future, he comes to a stop. The air is bitter cold, and the only sign of life is lichen on the beach. Small flakes of snow float in the air. A large disc begins to eclipse the sun; the Time Traveller suspects that some inner planet, perhaps Mercury, which is now much closer to Earth, is passing in front of the sun. An incredible darkness and blackness follows. On the verge of fainting, he climbs back on the machine, and as he does he notices a black blob with tentacles flop over in the distance. It is the only evidence of animal life.
As he travels back in time, he is eventually able to breathe with ease. He sees the dim outlines of buildings, and as he slows down, the walls of his laboratory again surround him. He sees his maid walk backward across the room. He stops the machine, stumbles out to check the date, and enters the dining room where he finds his guests.
The guests are speechless, and apparently very skeptical. For a moment, the Time Traveller's memory seems to falter, overwhelmed. He rushes to look at the time machine, and there it is, covered with dirt and grass. The next day, the narrator returns, eager to speak to his host in the clarity of daylight. The Time Traveller is about to leave on another journey, and promises to be back in half an hour, with hard evidence. But at the time the narrator is telling the story, three years have passed, and the Time Traveller has never returned. The narrator wonders where he could be, and knows only that he has two very brittle, alien flowers to show that time travel ever happened, proof that the human spirit of tenderness lives on even after strength and mind have decayed.
Having finished the adventure tale of the Eloi and the Morlocks, Wells now turns his Time Traveller to adventures more directly related to time travel. Wells delights in discussing the future in terms of astronomy and evolution. His imagery is closely related to the theory of entropy, the theory that the universe will ultimately decay into a state of inert uniformity.
The specifics of Wells pessimistic view of the future is admirable, but the fact that he includes science in his adventure tale is remarkable in itself. Today, science fiction is a well-established genre, but in his day Wells was one of its first practitioners.
I think it's important to realize that when the time traveller leaves in the end, he has with him a bag and a camera, so the reader can infer that he will return with proof.