My dear Mr. Clark:
As you are leaving office I want to express to you my sincere appreciation of your kindness in consenting to remain in the Department of State until the appointment of a new Under Secretary. Your knowledge of Mexican affairs has been invaluable to the Administration and I am sure that your advice during the dangerous days of the revolution went far toward keeping this Government to the wise course which has proved so successful.
I wish you all possible success in your future work.
Yours faithfully,
HERBERT HOOVER
[Honorable J. Reuben Clark, Department of State ]
Herbert Hoover, Letter on the Resignation of J. Reuben Clark as Under Secretary of State. Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/208667