Sea of Glory by Nathaniel Philbrick

America's bid to rule the waves

Exploration has traditionally had as much to do with the banishment of myth as the discovery of reality. So while Columbus died thinking he had found a new route to the East Indies, the first Portuguese caravels pushing down the West African coast in the 15th century took the River Senegal to be a branch of the Nile. Legend and received wisdom experienced drawn-out deaths.

While explorers usually succeeded in killing off one type of legend, their exploits often created another. These days, books are constantly emerging on one of the Antarctic greats (Scott, Shackleton and Cherry-Garrard), on explorers of the Sahara, or the great navigators: Columbus, Cook and FitzRoy. The appetite for exploration cannot be fully sated by modern travellers, and accounts of past feats now meet the demand.

The American writer Nathaniel Philbrick has a passion for such legendary adventures. His last book, In the Heart of the Sea, recounted the story which was the basis for Melville's Moby -Dick; now he has chronicled the greatest US voyage of exploration, the "South Seas Exploring Expedition" of 1838-42.

The so-called "Ex.Ex" was an important feat of scientific exploration. Circumnavigating the globe, and charting the coastlines of Tierra del Fuego, 1,500 miles of Antarctica, the archipelagoes of Fiji and Hawaii, and the Columbia River in the Pacific North-West, it placed the Americans on an equal footing with other powers in the race to uncover the world. Philbrick's elegant and meticulously researched book does a fine job of showing how important the Ex.Ex was to the emergent American nation.

The survey of the islands of Fiji, for instance, was said to be essential because Americans had so much of the trade there. As a growing power, the US needed not only the kudos of active discoveries - such as the first sighting of the Antarctic continent, on this trip - but the expansion of commerce: something which exploration, from Columbus to Stanley, has always abetted.

This aim had to contend with the Ex.Ex's difficult leader, Charles Wilkes. In a searing portrait, Philbrick enters into Wilkes's emotions, and relations with others, with the expertise of a novelist. Wilkes was what Philbrick calls an archetypal martinet. He ruled by a combination of arbitrary dismissal, brutality and mendacity. The purpose was both to claim all the credit for the Ex.Ex, and win everlasting fame. Yet Wilkes's very ambition proved self-destructive; he created so many enemies that he faced a court-martial on his return.

There is something paradigmatic about the Ex.Ex. The first stages of the voyage, in Tierra del Fuego and Antarctica, were most enjoyed by the sailors, as they revelled in the ice-caps and wild coasts. In Fiji, the atmosphere soured. A provisioning trip to the village of Malolo turned into a bloodbath: the people, thinking the Americans were shooting at them, killed two sailors. The Americans, who thought Fijians were about to eat them, responded by razing Malolo to the ground.

Though voyages of exploration have traditionally been seen as romantic feats of derring-do, such mutual fear and incomprehension often led to this sort of tragedy. It seems to be no accident that scientific voyages such as the Ex.Ex concentrated on surveying the land, and gave short shrift to the peoples. As the philosopher Tzvetan Todorov memorably put it, Columbus discovered America, but not the Americans.

Philbrick's book brings the motivation and nature of exploration into sharp relief. Although set long in the past, his maritime subject resonates with modern concerns. Of all today's adventurers, it is possibly sailors who excite most interest. Epic stories from the oceans have become a regular feature of news bulletins and publishers' catalogues.

With all the land masses now known, the emptiness of the sea remains to be discovered. We know that, at least in in the ocean, our consciences will be free of those peoples who once terrified - and were terrified by - the legendary explorers.

Toby Green's book 'Thomas More's Magician' will be published by Weidenfeld & Nicolson next month