13. (1) The Collector or any officer empowered by general or special order of the Government in this behalf shall have free access at all reasonable times during working hours to any mill or to any part of any mill. (2) The Collector or any such officer may, at any time during working hours, with or without notice to the owner, examine the purchase, sale and stock records and accounts of any mill and take copies of or extracts from all or any of the said records or accounts for the purpose of testing the accuracy of any return or of informing himself as to the particulars regarding which information is required for the purposes of this Act or any rules made thereunder: Provided that nothing in this section shall be deemed to authorise the examination of any description or formulae of any trade process.