I haven't made any decision about the new Minister to China. There are several names under consideration. One of them is Mr. [John Van A.] MacMurray of the [State] Department. My hesitation about him is to decide whether he would be of more value here in Washington serving in the Department, or of more value in China. He is an expert on Eastern affairs in the State Department—not the only one, but he is regarded as the chief expert.
Source: "The Talkative President: The Off-the-Record Press Conferences of Calvin Coolidge". eds. Howard H. Quint & Robert H. Ferrell. The University Massachusetts Press. 1964.
Calvin Coolidge, Excerpts of the President's News Conference Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/349102