§ 6. Call of the Senate. For the purpose of securing the attendance of
Senators, a call of the Senate may be ordered at any time, but such call
shall not be in order after the voting on any question has begun, nor
after the third reading of a bill has been completed, nor after the
motion to close debate has been ordered pursuant to section three of
this Rule, unless it shall appear upon an actual count by the Presiding
Officer that a quorum is not present.