The Mayor shall furnish to the Council, with the estimate hereinbefore mentioned, an ordinance making appropriations for the expenditures of the City during the year embraced by said estimate. The Council shall adopt such ordinance in its original form or with such revisions as it may deem proper within ninety days from the beginning of the fiscal year. The Council may amend or supplement said appropriation ordinance after its passage. Council may make one or more preliminary appropriations for current expenses until the annual appropriation ordinance is in effect.