What is "to put into the chair"

Chair \Chair\ (ch[^a]r), n. [OE. chaiere, chaere, OF. chaiere, chaere, F. chaire pulpit, fr. L. cathedra chair, armchair, a teacher's or professor's chair, Gr. ? down + ? seat, ? to sit, akin to E. sit. See Sit, and cf. Cathedral, chaise.]

1. A movable single seat with a back.

2. An official seat, as of a chief magistrate or a judge, but esp. that of a professor; hence, the office itself.

   The chair of a philosophical school.
   --Whewell.

   A chair of philology.
   --M. Arnold.

3. The presiding officer of an assembly; a chairman; as, to address the chair.

4. A vehicle for one person; either a sedan borne upon poles, or two-wheeled carriage, drawn by one horse; a gig.
   --Shak.

   Think what an equipage thou hast in air, And view with scorn two pages and a chair.
   --Pope.

5. An iron block used on railways to support the rails and secure them to the sleepers.

   Chair days, days of repose and age.

   To put into the chair, to elect as president, or as chairman of a meeting.
   --Macaulay.

   To take the chair, to assume the position of president, or of chairman of a meeting.