Seconding

Seconding is an arrangement by which officers of the British army, when extra-regimentally employed, become supernumeraries in their regiments, and have their places filled by others, so that the service may not suffer. Thus, a captain appointed adjutant of yeomanry, militia, or volunteers is placed upon the seconded list for the five years during which his appointment lasts. His place in the regiment is filled up, but his name (in italics) remains in its usual place in the Army List, his promotion goes on, and he is brought back at the end of his employment as soon as a vacancy occurs in his proper rank.