Executive Order—Amendment of Civil Service Rules
Special Departmental Rule No. I is hereby amended so as to include among the exceptions from examination in the Department of Agriculture the following:
Scientific or professional experts to be employed in investigations specially authorized by Congress, but not to include any persons regularly employed in that Department nor any persons whose duties are not scientific or professional, and who are not experts in the particular line of scientific or professional inquiry in which they are to be employed.
Approved, January 29, 1890.
Benjamin Harrison, Executive Order—Amendment of Civil Service Rules Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/205249