Two novellas by the incomparable H.G. Wells: First, The Invisible Man - A scientist theorizes that if a person's refractive index is changed to exactly that of air his body does not absorb or reflect light, then he will not be visible. He successfully carries out this procedure on himself, but cannot become visible again, becoming mentally unstable as a result.
Next, The Time Machine - Follow the Time Traveller to the year 802,701 A.D. He finds a golden race of small, soft, innocent people. but what is it that lurks in the dark shadows? And what happens when the time machine is stolen?