( 1 ) SUB-SECTION (4) of section 8 of the Central Sales Tax Act, before its amendment in 1976, read as follows :" (4) The provisions of sub-section (1) shall not apply to any sale in the course of inter-State trade or commerce unless the dealer selling the goods furnishes to the prescribed authority in the prescribed manner - (a) a declaration duly filled and signed by the registered dealer to whom the goods are sold containing the prescribed particulars in a prescribed form obtained from the prescribed authority; or (b) if the goods are sold to the Government, not being a registered dealer, a certificate in the prescribed form duly filled and signed by a duly authorised officer of the Government. "

( 2 ) AS contemplated by this sub-section, rules were made by several States prescribing the time within which C forms - with which alone we are concerned in this case - were to be filed. One of the rules framed by the Kerala State, provided that the C forms should be filed along with the declaration, but in any event before the assessment is made. This rule was struck down by the Supreme Court in Sales Tax Officer v. Abraham [1967] 20 STC 367 (SC), as travelling beyond