12/08/1909
https://www.presidency.ucsb.edu...
"All communications to the Department of State should be addressed to the Secretary of State."
"Despatches should be written on one side only of single-sheet despatch paper."
"Despatches regarded as especially of a reserved or secret nature should be conspicuously marked 'Confidential' on the top of the first page."
"The business of the department pertaining to civil government in Porto Rico is, pursuant to Section 87 of the Act of July 1, 1902, assigned to the Bureau of Insular Affairs."