Section 8. All books kept by the collector, which shall be approved as to form by the commissioner, shall be furnished by, and be the property of, the town, and shall be at all reasonable times open to examination by the auditor of such town or any other agent thereof duly authorized therefor. The collector shall, on demand by the mayor, aldermen or selectmen, exhibit to them or to any persons whom they designate, at any time during ordinary business hours, the books, accounts and vouchers relating to taxes committed to him for collection and to his receipts and payments on account of taxes; and they, or the persons designated by them, shall have full opportunity to examine said books, accounts and vouchers, and to make copies and extracts therefrom.