For oil trespass in a State where there is no State law governing such trespass, the measure of damages will be as follows:

(a) Innocent trespass. Value of oil taken, less amount of expense incurred in taking the same.

(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).