This article, now repealed, previously defined the tax base for the natural gas investment tax. It stipulated that the tax base was the gross income specified under Article 46, less any expenses deductible under the Law. The text explicitly clarified that payments for royalties and surface rentals were to be treated as deductible expenses for the purpose of this calculation. The provisions of this article were officially repealed by Royal Decree No. M/70, with the repeal taking effect from 1 January 2018, thereby removing this specific tax base calculation from the current legislation.