Special meetings of the Board of Trustees may be called by the
Mayor or by any two Trustees, by causing a written notice, specifying
the time and place thereof, to be served upon each member of the Board,
personally, at least one hour, or by leaving a notice at his residence
or place of business with some person of suitable age and discretion,
at least 24 hours, before the time of meeting, or by mailing such
notice at least 72 hours before such meeting.