G was first measured by henry cavendish, the newspaper report it as the weighing of the earth experiment. because when henry cavendish measured the value of G, this allows physicist to calculate the mass of the earth using the newton's law of gravitation.
Because most were illiterate since they were denied a chance at gaining an education before since they were considered slaves and not a technically a US citizen that had full rights. After the Civil War through certain laws they were finally allowed to get an education.
Answer: Former slaves like Frederick Douglass and Harriet Tubman spread the word about how slaves were treated in the south by writing newspapers and books, like the North Star Newspaper (Douglass), and the novel Uncle Tom's Cabin (Tubman).