Pending the application of the proceeds of any bonds issued under the provisions of this chapter to the purpose for which such bonds have been issued, all or any part of such proceeds may be invested, upon resolution of the school board, in securities that are legal investments under the laws of this Commonwealth for public sinking funds, which shall mature, or which shall be subject to redemption by the holder thereof at the option of such holder, not later than the date on which the moneys will be required to make the payments for which such moneys have been designated. Any security so purchased as investment of the proceeds of such bonds shall be deemed at all times to be a part of such proceeds, and the interest accruing thereon and any profit realized from such investment shall be credited to such proceeds. Any security so purchased shall be held by the treasurer or chief financial officer of the county, city or town, and shall be sold by him upon resolution of the school board directing such sale, at the best price obtainable, or presented for redemption, whenever it shall be necessary, as determined by such resolution, in order to provide moneys to meet the purpose for which the bonds shall have been issued.