Could a transcontinental expedition of the Lewis & Clarke type have been mounted by the British colonial authorities in North America during the 18th century? This specifically refers to an expedition that departs from the westernmost point of British settlement with the objective of reaching the Pacific, with a return journey organized by either land or sea. Assuming the political/scientific motivation for such an expedition existed, and assuming it had permission from France and/or Spain to traverse their territories, how early could such an expedition have been feasibly mounted? Could it have been accomplished as early as the 17th century?