Council may in its discretion direct investment of any surplus, reserve, or inactive funds into such investments as are permitted by general law. Such investments shall be supervised by a board consisting of the Manager, the Director of Finance, and three Councilmen chosen by majority vote of all members of Council. Each Councilman is to serve for a term expiring on the date of expiration of his term as Councilman. Council may also authorize the purchase of short term Certificates of Deposit with the Municipal Depository, provided such certificates may be redeemed by giving thirty days notice to such Depository.