What year is the immigration tide in the history of China?

The history of China people going to the New World began at 1820, when there were not many people. Arrived at 1854, the US Immigration Bureau suddenly had the immigration record of 13 100 from China, and then flooded into the United States year after year. So the maximum year should be 1854. But these immigrants are not real immigrants. The main reason for this immigration wave is that 1848 discovered gold in the Sacramento Valley in western North America, and joined the United States of America to become California two years later. At that time, California was sparsely populated and lacked labor, and the Trans-American Railway had not yet been built. It took three to six months to travel from the eastern part of the United States to the western part. However, it only takes two to three months to fly from Hong Kong to San Francisco. At this time, China has just been opened to the outside world by western powers by force, so recruiting China laborers has become an important way to solve the serious shortage of labor in the western United States. In addition, Chinese workers are all free laborers, which can prevent the expansion of slavery in the United States. Therefore, American entrepreneurs aim at China with a large population, hunt for labor and develop the so-called "coolie trade". Look at this page to learn more about the history of immigrants in China. /article/ 1530559.html