Umbriel, 243.
Umbriel, Distance and Period of, 392.
Universe, Seen and Unseen, 377.
“Up, Guards, and at them,” 337.
Uranus and Earth compared, 243.
Uranus, Clouds on, 243.
” Color of, 242.
” Diameter of, 391.
” Discovery of, 237.
” Distance of, 391.
Uranus, Former Observations of, 241.
Uranus, Period of, 391.
” Rotation of, 391.
” Satellites of, 242.
Uranus, Satellites of, Distances and Periods of, 392.
Uranus, Time of Revolution, 213.
” Weight of, 243.
Ursa Major, or Great Bear, 381.
Use of Two Eyes, 19.
Utility of Telescope, 200.