Week 5: Longitude by Dava Sobel (Penguin, 1995, paperback)
Dava Sobel, in this eloquent short book explores “The active quest for a solution to the problem of longitude [that] persisted over four centuries and across the whole continent of Europe” (7). During the great age of ocean exploration, latitude (the concentric grid lines from the equator to the poles) could be determine by “Any sailor work his salt . . . by the length of the day, or by the height of the sun or known guide stars above the horizon” (4). Determining longitude (the circles from North Pole to South Pole) was much more difficult, as it required knowing time at sea and time at a fixed point on land; the difference between indicated the distance traveling east to west, and vice versa.
The problem, as Sobel describes, is that no reliable timepiece existed that could travel at sea and keep consistent time. The problem was so significant and important for sea travel that British Parliament in 1714 set a million dollar prize (in adjusted amounts) for anyone that could provide a “Practicable and Useful” (8) solution to the problem. Sobel’s book focuses on this great mechanical and scientific challenge through the experiences of James Harrison, an uneducated clockmaker and his lifelong work on solving this problem, through the creation of clocks that could travel the seas. Harrison is Sobel’s agreeable hero, struggling against the astronomers who sought answers in the stars and the movements of the planets and blocked his claims to the prize money.
While science is the context of this story, Sobel’s gift is to make the story and the men involved the real appeal. Through her uncluttered phrasing and relaxed style, we are able to understand the achievements that Harrison brought to this challenge. We come to admire the intricacies of his different mechanical marvels through her descriptions, and her narrative shows us the real people behind the historical events. While her need to cast the astronomers as the villains may be a bit unnecessary, overall we trust her depictions are honest as we follow Harrison’s successes and struggles.
Sobel has written an informative, engaging book on a little-know historical event. Her book should be embraced by anyone looking to better understand the devices and people who provided the necessary innovations to help us explore our world.
Next week . . . Perma Red by Debra Magpie Earling.