In the United States, there was a movement to resettle American free blacks and freed slaves in Africa. The American Colonization Society was founded in 1816 in Washington, DC for this purpose, by a group of prominent politicians and slaveholders. But its membership grew to include mostly people who supported abolition of slavery. Slaveholders wanted to get free people of color out of the South, where they were thought to threaten the stability of the slave societies. Some abolitionists collaborated on relocation of free blacks, as they were discouraged by discrimination against them in the North and believed they would never be accepted in the larger society. Most African Americans, who were native-born by this time, wanted to improve conditions in the United States rather than emigrate. Leading activists in the North strongly opposed the ACS, but some free blacks were ready to try a different environment.
rather than emigrate African Americans wanted to do what?
improve conditions in the United States

When an electromagnetic wave strikes a plane surface such as the ground, part of the wave is transmitted into the ground and part of it is reflected, according to the Fresnel coefficients. If the ground is a very good conductor then almost all of the wave is reflected (180 out of phase), whereas a ground modeled as a (lossy) dielectric can absorb a large amount of the wave's power. The power remaining in the reflected wave, and the phase shift upon reflection, strongly depend on the wave's angle of incidence and polarization. The dielectric constant and conductivity (or simply the complex dielectric constant) is dependent on the soil type and is a function of frequency.
Who proposed this theory?
Fresnel coefficients

Even interpreting the hydrogen data (including safety data) is confounded by a number of phenomena. Many physical and chemical properties of hydrogen depend on the parahydrogen/orthohydrogen ratio (it often takes days or weeks at a given temperature to reach the equilibrium ratio, for which the data is usually given). Hydrogen detonation parameters, such as critical detonation pressure and temperature, strongly depend on the container geometry.
What do Hydrogen detonation parameters depend on?
container geometry