The board of supervisors immediately after their election or appointment shall meet at some convenient place and choose one of their number president of the board and elect some suitable person secretary, who may or may not be a member of the board and who may be required to execute bond for the faithful performance of his duties as the board of supervisors may require. The board may adopt a seal with a suitable device and shall keep a record of all its proceedings in a substantially bound book to be kept for the purpose, which shall be open to inspection by any interested person, his agent or attorney.