Section 17. If any dutiable yarn is exported by sea to any foreign port before the return in respect of it has b

17. If any dutiable yarn is exported by sea to any foreign port before the return in respect of it has been delivered to the Collector under section 7, the owner of the mill in which it was produced may apply to the Collector at the port of shipment, who, on being satisfied that such yarn has actually been shipped for export, shall grant him a certificate stating the quantity and particulars of such yarn, and that it has actually been so shipped.