The place of humans in the world of nature is essential to David Barrie’s wonderfully descriptive story of the sextant. I always have been fascinated by the interdependent relationship of people and nature. I am convinced that technology mediates this relationship, and Barrie confirms my belief. The tale of the sextant is that of one of several tools in the history of maritime navigation technology — others include the astrolabe, back-staff, cross-staff, quadrant, compass and chronometer.& It was the principal navigation tool of mariners for the past three centuries, eclipsed only in the last forty years by GPS. It also was one of the basic surveying tools that made possible charting coastlines and oceans with some modicum of accuracy.

Barrie, an experienced life-long sailor, begins his story with his own reminiscences of his father’s love of astronomy and cartography and of his first transatlantic crossing at age nineteen with retired Royal Navy captain Colin McMullen on a thirty-five-foot sloop.  McMullen introduced the secrets of the sextant to Barrie, teaching him to take his first “mer alt” (the sun’s meridian altitude). His Atlantic crossing is woven through the rest of the book, which looks at the origins of the sextant and other navigation instruments and then, with the sextant foremost in the telling, to the stories of a dozen navigators and explorers who crisscrossed the oceans, discovering and charting islands and coastlines.

Most readers will probably be familiar with the adventures of the almost one-dozen mariners and explorers whose stories Barrie recounts, but when couched in the tale of the sextant itself, each one takes on new meaning.  We all know the story of Captain William Bligh, whose ship, the Bounty, was wrested from him by mutineers in the south Pacific. It was his remarkable skill with a sextant, however, that made it possible for him to take what was left of his crew in a small skiff a distance of 3,600 miles to the Dutch West Indies. Similarly, you may know the story of Captain James Cook, commander of the Endeavor, who carried scientists from Britain to Tahiti to observe the second “Transit of Venus” that occurred in the eighteenth century, as well as to explore the south Pacific. “In the course of his three great voyages of discovery, Cook, with sextant in hand, added more to European knowledge of the Pacific Ocean than any other single person.”

The adventures of other navigators, some well-known and some not-so-well known, include Louis-Antoine de Bougainville (best known today for the plant named after him), who explored the south Pacific for France in the late eighteenth century, and George Vancouver for whom Vancouver Island, as well as a city in British Columbia and one in the state of Washington, is named. Another French navigator, Jean-François de Galaup La Pérouse, visited the coast of California and explored the Pacific Northwest and Alaska before heading for the south Pacific where his two ships with two hundred men disappeared while in search of the Solomon Islands. Only in recent years have the wreck sites of Pérouse’s two ships been identified near Vanikoro in the Santa Cruz group of islands southeast of the Solomons. Matthew Flinders, who sailed under William Bligh after the mutiny on the Bounty, explored routes along the northern coast of Australia and suffered enormous hardships plus captivity by the French. The voyages of the Beagle, famous for carrying Charles Darwin to the Galapagos Islands, sailed under more than one captain who possessed great skill with the sextant.

Sextant closes with the story of Joshua Slocum’s well-known singlehanded circumnavigation in Spray and with the gripping story of early-twentieth-century explorer Sir Ernest Shackleton on Endurance. Heading for Antarctica, in February 1915, Endurance became entrapped in closing ice some sixty miles from her planned destination. In October, Shackleton and his ship’s captain, Frank Worsley, decided to abandon ship and make camp on the snowpack. Five months later, in April 1916, Worsley with Shackleton and their crew of twenty-eight seamen reached Elephant Island, whence they and four of the crew members set sail in a 23-foot ship’s boat on a voyage of 800 nautical miles across the Southern Ocean to South Georgia. The sextant proved to be their most important navigational tool.

Toward the beginning of Sextant, Barrie devotes two chapters to the “longitude problem” and the chronometer which finely resolved it, but he’s much better with the sextant. So, the moment you put down this fascinating and engaging book, you’ll want to turn to someone who is as passionate about the “longitude problem” as Barrie is about the sextant. That should be Dava Sobel’s Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time (1995), the story of eighteenth-century English clockmaker John Harrison who, in a forty-year quest to beat the “longitude problem,” developed the chronometer, a clock that kept precise time at sea, something no clock had ever been able to do before, even on land.

Sextant: A Young Man’s Daring Sea Voyage and the Men Who Mapped the World’s Oceans by David Barrie (William Morrow, 2014, 240 pages)