| (a) | - | in a case where the rate of duty as specified in the Fourth Schedule as in force immediately before the issue of such notification is nil, a rate of duty not exceeding fifty per cent. ad valorem expressed in any form or method; |
| (b) | - | in any other case, a rate of duty which shall not be more than twice the rate of duty specified in respect of such goods in the Fourth Schedule as in force immediately before the issue of the said notification: |