At the end of that period, ten percent (five) of them would research into and advance air exploration. And much further into the last century of the millennium, another quarter of those US explorers would be pioneers in the exploration of space. Only ten percent (six) American explorers would continue researching into the mysteries of the oceans, continuing a process well established by older nations. American exploration began by stretching westward on land, following the Louisiana Purchase (1803).

Map of the New Hebrides (now called Vanuatu) and New Caledonia Rome, 1798 in Atlas of the World Sforesco Castle, Milan