The county board may adjourn from time to time in the discharge of its duties, and may, after investigation, revise, correct and equalize the assessed value of all property in the respective taxing districts, increase or decrease the assessed value of any property not valued at its taxable value, assess property omitted from any assessment, as provided by law, at its taxable value, and in general do everything necessary for the taxation of all property in the county at its taxable value.
N.J.S. § 54:4-47