4. Time within which appeal is to preferred.- (1) An appeal shall be preferred by the aggrieved person within a period of thirty days from the date of communication to him of the order of the Board made under the Act or rules or regulations. (2) When the appeal is preferred after the expiry of the period of thirty days specified in sub- rule (1), it shall be accompanied by an application supported by an affidavit setting forth the facts on which the appellant relies to satisfy the Central Government that he has sufficient cause for not preferring the appeal within the said period of thirty days: Provided that if the Central Government is satisfied that the appellant had sufficient cause for not preferring the appeal within the aforesaid period, it may; for reasons to be recorded in writing, admit the appeal after the expiry of the aforesaid period but before the expiry of 45 days from the date of communication to him of the order of the Board. | 