An Act to enable Her Majesty to carry into effect certain Stipulations contained in a Treaty of Commerce and Navigation between Her Majesty and the Emperor of Austria; and to empower Her Majesty to declare, by Order in Council, that Ports which are the most natural and convenient Shipping Ports of States within whose Dominions they are not situated may in certain Cases be considered, for all Purposes of Trade with Her Majesty's Dominions, as the National Ports of such States.