The history of Chinese Americans or the history of ethnic Chinese in the United States includes three major waves of Chinese immigration to the United States, beginning in the 19th century. Chinese immigrants in the 19th century worked in the California Gold Rush of the 1850s and the Central Pacific Railroad in the 1860s. They also worked as laborers in Western mines. They suffered racial discrimination at every level of society. The white people were stirred to anger by the "Yellow Peril" rhetoric. Despite provisions for equal treatment of Chinese immigrants in the 1868 Burlingame Treaty between the U.S. and China, political and labor organizations rallied against "cheap Chinese labor". Newspapers condemned employers who were initially pro-Chinese. When clergy ministering to the Chinese immigrants in California supported the Chinese, they were severely criticized by the local press and populace. So hostile was the opposition that in 1882, the U.S. Congress passed the Chinese Exclusion Act prohibiting immigration from China for the following ten years. This law was then extended by the Geary Act in 1892. The Chinese Exclusion Act was the only U.S. law ever to prevent immigration and naturalization on the basis of race. These laws not only prevented new immigration but also the reunion of the families of thousands of Chinese men already living in the United States who had left China without their wives and children. Anti-miscegenation laws in many Western states also prohibited the Chinese men from marrying white women. In the South, many Chinese American males married African American women. For example, the tenth U.S. census of Louisiana alone showed 57% Chinese American men were married to African American women, and 43% to European American women. In 1924, the law barred further entries of Chinese. Those already in the United States had been ineligible for citizenship since the previous year. Also by 1924, all Asian immigrants (except people from the Philippines, which had been annexed by the United States in 1898) were utterly excluded by law, denied citizenship and naturalization, and prevented from owning land. In many Western states, Asian immigrants were even prevented from marrying Caucasians. Only since the 1940s, when the United States and China became allies during World War II, did the situation for Chinese Americans begin to improve, as restrictions on entry into the country, naturalization, and mixed marriage were lessened. In 1943, Chinese immigration to the United States was once