Zheng He was a Chinese explorer who lead seven great voyages on behalf of the Chinese emperor. These voyages traveled through the South China Sea, Indian Ocean, Arabian Sea, Red Sea, and along the east coast of Africa. His seven total voyages were diplomatic, military, and trading ventures, and lasted from 1405 – 1433.
1: Mary Prince is saying that they do not feel happy in the slightest because they are treated so horribly.
2: Prince says, "How can they be happy with a halter around their neck and a whip upon their back, and are discraced."
3: The English, "Forget God and shame." People may change into this because they are not ashamed of their actions.
4: The fact that she has escaped slavery makes it more effective in my opinion because it shows that she wanted to be free. That being free is the only way she could be happy.
Robert Boyle wrote and published "The Sceptical Chymist: or Chymico-Physical Doubts & Paradoxes" in 1661. Sir Isaac Newton wrote many works but could be best remembered for "The Principia: Mathematical Principles of Natural Philosophy" in 1726. Both of these works could be considered the beginning of the scientific revolution (though I do not believe that either Boyle or Newton would want "revolution" term used in later discoveries as a result of their work.)
