Answer:
The purpose of this source is to provide information about John Hay, an American statesman and official, and his role in proposing equal trading rights in China for all nations in 1899. The source also mentions the involvement of the United States in the Boxer Rebellion, including the deployment of marines.
The intended audience of this source could be anyone interested in learning about John Hay, American foreign policy in China, or the Boxer Rebellion. This may include students, scholars, historians, or individuals with a general interest in American history and international relations.