ALA Booklist

In the 1700s navigators could easily compute latitude, but finding longitude was nigh impossible. So valuable was a solution in terms of saving ships from fetching on rocks that England offered a munificent prize for a practicable method, and soon two avenues offered themselves. An accurate chronometer occupied the thoughts of clockmaker John Harrison, and a tediously compiled catalog of the stars, against which the moon could be used as a clock, was pursued by astronomers. Sobel presents the contest's course with a stylish mix of technical and human insight that emphasizes Harrison's life and dealings with the stingy Board of Longitude, custodian of the prize. When his contraption, the fruit of decades of solitary labor, went to sea and seemingly met the requirements, the Board balked, not least because one of its members was the very astronomer working on the celestial method. His glory dimmed by raw rivalry, Harrison fell into obscurity, and his chronometers into disrepair until restored 60 years ago. Completing the rehabilitation, Sobel's is an exquisitely told tale of perseverance, disappointment, and vindication. (Reviewed Sept. 1, 1995)

Kirkus Reviews (Thu Apr 28 00:00:00 CDT 2022)

The subtitle here tells the reader exactly what the book is about; what it doesn't say is how much fun it is to read. The Greek astronomers could measure latitude as early as the third century b.c., but more than 2,000 years passed before the development of a reliable method for measuring longitude. Former New York Times reporter Sobel (coauthor, Arthritis: What Works, 1989, etc.) sets the stage by recounting the difficulties early navigators had in determining their exact longitude. After the loss of many ships and human lives as a result of navigational errors, in 1714 Parliament offered a rich prize for a practical way to measure longitude at sea. British astronomers saw a solution in the stars, by making sufficiently accurate measurements of lunar positions and comparing them to positions calculated for a known reference point. But the calculations could take hours and were tricky even in the best of circumstances; one future astronomer royal, under pressure, botched a measurement of the longitude of Barbados. Enter John Harrison, an apparently self-taught English clockmaker. Over a period of 40 years, he developed four increasingly precise chronometers capable of holding accurate time over a long, rough sea voyage. Comparing the chronometer's time to local sun time, a navigator could measure longitude with high precision in short order. Despite fierce opposition from astronomers (who scorned a ``mere mechanic''), Harrison's clocks were enthusiastically endorsed by every mariner who put them to the test (including such luminaries as Cook and Bligh). With the support of King George III, the clockmaker eventually prevailed and won the prize. Sobel tells his story (and the larger history of the search for longitude) clearly, entertainingly, and with a fine sense of the era in which it took place. Breezily written and full of fascinating characters and facts, here's a science book as enjoyable as any novel."

School Library Journal

YA--Opening with a chapter that outlines what follows, Sobel whets readers' appetites for hearing the colorful details of the search for a way for mariners to determine longitude. In an age when ships' stores were limited and scurvy killed many a seaman, missing a landfall often meant death--as, of course, did running aground. Sobel provides a lively treatment of the search through the centuries for a ready answer to the longitude problem, either through using lunar tables or through making an accurate clock not subject to the vicissitudes of weather and ocean conditions. Her account includes not only scientific advances, but also the perseverance, pettiness, politics, and interesting anecdotes that figured in along the way (it wasn't limes, for example, that first prevented scurvy on English ships, but sauerkraut). A pleasing mixture of basic science, cultural history, and personality conflicts makes this slim volume a winner.--Judy McAloon, Potomac Library, Prince William County, VA