9239.5-2—Oil.
         For oil trespass in a State where there is no State law governing such trespass, the measure of damages will be as follows:
    
    
    
        
        (b) Willful trespass.
         Value of the oil taken without credit or deduction for the expense incurred by the wrongdoers in getting it. Mason v. United States (273 Fed. 135).