Structure of the Earth Structure of the Earth The internal structure of the Earth is layered in spherical shells: an outer silicate solid crust, a highly viscous asthenosphere and mantle, a liquid outer core that is much less viscous than the mantle, and a solid inner core. Scientific understanding of the internal structure of the Earth is based on observations of topography and bathymetry, observations of rock in outcrop, samples brought to the surface from greater depths by volcanoes or volcanic activity, analysis of the seismic waves that pass through the Earth, measurements of the gravitational and magnetic fields of the Earth, and experiments
What to the Slave Is the Fourth of July? under the sea, as well as on the earth. In the United States, the speech is widely taught in history and English classes in high school and college. American studies professor Andrew S. Bibby argues that because many of the editions produced for educational use are abridged, they often misrepresent Douglass's original through omission or editorial focus. The speech has been notably performed or read by important figures, including the following actors: What to the Slave Is the Fourth of July? "What to the Slave Is the Fourth of July?" is the title now given to a speech by Frederick