(d) Royalties for Use of Patents, Copyrights, Trade-Marks, Secret Processes, Formulæ and Similar Income
48. As a rule, such royalties are not taxable, and, in fact, there are very few instances where foreign patents, copyrights, etc., are licensed to local enterprises.
49. Foreign enterprises having an establishment within N.E.I., and engaged in the profession of buying and selling copyrights, are taxable on the income derived therefrom.