Each year the council shall appoint three of its members who shall act as a board of equalization, which board shall meet on the second and third Mondays in August at 11:00 o’clock in the forenoon, and on such other days during said month as may be necessary or desirable, for the purpose of equalizing assessments. Said board of equalization shall have power to hear complaints and to correct, modify, strike out, lower or raise any assessment; provided, that at least five days’ notice shall be given to the party whose assessment is to be changed. The city clerk shall act as secretary of such board and it shall be the duty of such secretary to keep permanent records of all proceedings, and to enter therein all resolutions and decisions of the board.