Tariff exemption for gases used in heavy water manufacture clarified, limited to gases when so used. The Government amended Notification No. 7/94-C.E. to substitute, in the Table against S. No. 4, the entry in column (4) with the condition 'If used in the manufacture of Heavy Water.', thereby making the tariff concession for the specified gases conditional on their use in heavy water production under the statutory power to amend excise notifications.