The clerk of the board must record in his minute book all changes, corrections and orders made by the board, and during its session, or as soon as possible after its adjournment, must enter upon the assessment book or roll in red ink all changes and corrections made by the board, and on or before the fourth Monday in August must affix thereto, subscribed by him, an affidavit, as follows:

I, ______________, do swear that, as Clerk of the Council, sitting as a Board of Equalization of the City of Bakersfield, I have kept correct minutes of all acts of the Board touching alterations in the assessment book or roll; that all alterations agreed to, or directed to be made, have been made and entered in the book or roll, and that no changes or alterations have been made therein except those authorized.