Tides: The Science and Spirit of the Ocean


Tides: The Science and Spirit of the Ocean
by Jonathan White
Trinity University Press
San Antonio 

As a teenager besotted by the lure of sea and seafaring, I read whatever I could get my hands on about windjammer voyaging. The phrase “sailing on the tide” rattled knowingly around my head. Years later, as a merchant mariner, the rise and fall of the tides had a certain academic interest. But unless one’s vessel was laden to the marks, then the diurnal phenomena of ebb, flood and slack were hardly of the same critical importance to steam propulsion than they had been to ships of the so-called Golden Age of Sail.

In an indirect way, a new book brought — at least for me — both of those historic maritime eras instantly to mind. Though it barely touches on seafaring, Tides: The Science and Spirit of the Ocean suggests a broader canvas: the majesty and mysterious power of the sea.

Author Jonathan White is admirably suited to tell this story. A journalist, schooner captain and environmentalist, he personally pursued his subject from China’s coastal waters and the San Blas Islands near Panama, to as far north as the Arctic. He explores the relationship of tides to religion and natural history, and touches on what global warming means for tidal communities. He examines the prospect of tidal power as a source of green energy. He reports on Nova Scotia’s record tides in the Bay of Fundy that neared 55 feet between any given high and low water.

But for this reader, the heart of the book is White’s theoretical unraveling of the mechanism of tides. In his chapter on Sir Isaac Newton, the author outlines the 17th-century English physicist’s contributions to groundbreaking tidal theory. The key to the puzzle was the attractive force of the moon. And the name that Newton coined for it was “gravity.”

“The idea of a ghostly force spreading its fingers across vast distances was so unscientific,” says White, “that most natural philosophers wanted nothing to do with it. In a world yearning for mechanistic answers, gravity seemed a regression to the occult of antiquity.”

But Newton upended contemporary thinking. According to White, although the great scientist never discovered what gravity actually was — “only how it behaved” — he created a mathematical model of Earth and moon as central elements in tidal science. In a theory that essentially holds true today, Newton was able to demonstrate how the push and pull of gravity causes tides.

White ends his fine book on a spiritual note. “The tide teaches us to live with mystery and complexity,” he tells us. “It lives in the body of a mudshrimp, signaling when to swim and when to burrow. It lives in sandpipers, crabs, and whelks. … The tide is vibration, music, time.”

Jonathan White is not only an accomplished storyteller, but a rare exemplar of the marriage of technical lucidity with stylistic grace. His book was a joy to read.

By Ocean Navigator