(1)    Public museum funds appropriated to the museum by the common council shall not be used or appropriated, directly or indirectly, for any purpose other than the maintenance and increase, payment of the salaries of the employees, purchase of fuel, supplies, furniture and fixtures, or incidental repairs of the museum.

   (2)   All moneys appropriated for the purposes of said institutions shall be paid over to the city treasurer and credited to said funds, respectively. Each board of trustees shall provide for all necessary expenditures from each said fund, and all disbursements shall be made on orders of the president and secretary of the board, countersigned by the city comptroller; but, except as expressly provided otherwise, the board shall not in any one year expend or incur any liability for any sum in excess of the amount allocated to each such fund by the common council.