Special meetings of the Council may be called as provided by its rules, regulations, laws, resolution or ordinances. In the absence of any such provisions, special meetings may be called by a vote of Council taken at any regular or special meeting thereof or shall be called by the Clerk of Council on the written request of the Mayor, or the President of Council, or any three (3) members of Council. Any written request for a special meeting shall state the subject or subjects to be considered at the special meeting and no other subject or subjects shall be considered. Notice in writing of each special meeting called at the request of the Mayor, President of Council or three (3) members of Council shall state the date, time, place and subject or subjects of the special meeting and shall be posted on a bulletin board in the lobby of the City Hall and served on the Mayor and each member of Council either personally or by leaving a copy of such notice at his usual place of residence. Such posting and service shall be accomplished not less than twenty-four (24) hours preceding the time for the special meeting. In the event that a special meeting is called by a vote of Council taken at any regular or special meeting from which the Mayor or any member of Council is absent, written notice of such special meeting shall be posted and given each absentee in the manner hereinbefore described. Service of notice of any special meeting shall be deemed conclusively to have been waived by the Mayor or by any councilman who shall be present thereat.