The tone of The Time Machine is somber, contemplative, and—ultimately—cautionary. The Traveller's journey through time is a venture into the unknown, and the tone of the story reflects the mix of awe, wonder, and fear that he feels as he encounters the unfamiliar landscape of the future.
Throughout the book, Wells uses descriptive language to create a sense of the despair and decay he feels while displaced in time. The author delivers imagery of a world that is overgrown with vegetation and rife with crumbling buildings and statues. Beneath the beautiful veneer of the landscape lies the danger and depravity of the Morlock civilization, who steal the Traveller's vehicle and imbue the novel with a fearful and apprehensive tone.
The fear felt by the Eloi people towards the subterranean Morlocks gradually infiltrates the Time Traveller's consciousness, darkening the story's tone. The Traveller describes the Eloi people, who have devolved into fragility and fear:
It seemed to me that I had happened upon humanity upon the wane. The ruddy sunset set me thinking of the sunset of mankind.
The Traveller remarks that humanity is on the "wane"; although he sees marks of its zenith, human civilization is now in decline. This creates a sense of somberness and melancholy as the Time Traveller is confronted with the consequences of humanity's hubris, lack of foresight, and unrestricted social inequality.
Although the Time Traveller begins the narrative with a sense of the excitement and urgency of scientific exploration, this adventurous tone wilts when exposed to the dire consequences of humanity's technological "taming" of the natural world. This shift from optimism to disillusionment creates a tension between the adventurous spirit of exploration and the pessimistic conclusions the Traveller draws from his experience of the future. The later chapters of the story have a moralistic tone, as the writer urges the reader to consider the depravity and desolation that could result from continued social inequality. The Traveller believes he has witnessed the "sunset of humanity," and this experience, combined with his isolation and the fear inspired by the Morlocks, contributes to a melancholy and somber tone.