07/01/1886
https://www.presidency.ucsb.edu...
"Professional experts and special agents employed for short periods at per diem salaries and paid only when actually employed."
"Transfers may be made as follows:"
"the President hereby makes and promulgates the following rule to cancel and be in lieu of Customs Rule V of the Revised Civil-Service Rules"
"All vacancies, unless filled by promotion, transfer, or reappointment, shall be filled in the following manner:"