The Board of Finance and Revenue shall determine the amount of money necessary for the payment of interest on the bonds and the principal thereof, if any, for the two fiscal years beginning June first, one thousand nine hundred forty-seven, and the times and amounts of such payments, and the amount so determined shall be transferred from the Public Buildings Construction Fund to the Public Buildings Construction Sinking Fund, and for such purpose, as much of the money in the Public Buildings Construction Fund, as may be necessary, is hereby appropriated. Should the moneys in the Public Buildings Construction Fund, for any reason, not be available for the payment of interest on the bonds or the principal thereof, if any, the funds necessary for such purpose are hereby appropriated from the General Fund, and whenever any moneys are transferred from the Public Buildings Construction Fund for the payment of said interest on and principal of said bonds and such moneys are needed for the payment of the construction of public buildings, for anti-stream pollution projects and for flood control projects, as provided by law, there is hereby appropriated from the General Fund, a sum sufficient to restore to the Public Buildings Construction Fund the moneys so transferred.