law: 27. Power to make rules.-
  (1) The Board may, subject to the control of the Central Government, by notification in the Official Gazette, make rules for carrying out the purposes of this Act.
  (2) In particular, and without prejudice to the generality of the foregoing power, such rules may provide for all or any of the following matters, namely:-
  (a) the form in which returns under section 7 may be furnished and the manner in which they may be verified;
  (b) the form in which appeals under section 15 or section 16 may be filed and the manner in which they may be verified;
  (c) the procedure to be followed on applications for rectification of mistakes and applications for refunds;
  (d) any other matter which by this Act is to be, or may be, prescribed.
  (3) The power to make rules conferred by this section shall on the first occasion of the exercise thereof include the power to give retrospective effect to the rules or any of them from a date not earlier than the date of commencement of this Act.
  (4) The Central Government shall cause every rule made under this section to be laid, as soon as may be after it is made, before each House of Parliament while it is in session for a total period of thirty days which may be comprised in one session or in two or more successive sessions, and if, before the expiry of the session immediately following the session or the successive sessions aforesaid, both Houses agree in making any modification in the rule or both Houses agree that the rule should not be made the rule shall thereafter have effect only in such modified form or be of no effect, as the case may be; so, however, that any such modification or annulment shall be without prejudice to the validity of anything previously done under that rule.