Top positive review
great little book, though could do with some illustrations and diagrams
on 28 December 2016
This is an engagingly written non-specialist account of the hunt during the 18th century for an accurate way to measure longitude, and thus more accurately track sea voyages between west and east. While latitude had been understood since antiquity and has an absolute meaning relative to the north and south poles, longitude is entirely relative and can in principle be measured from any artificial line connecting the poles. The hunt was turned into a race by the British Parliament's Longitude Act of 1714, establishing a Board to consider proposals to measure longitude accurately, with a top prize of £20,000 for anyone able to measure it to within half a degree of accuracy. Why such a high profile prize? Ignorance of longitude was very costly, including costing the lives of many seamen, including two thousand in one incident in 1707 when four warships ran aground off the Scilly Isles. Ignorance also cost economically as it meant marine trade routes had to follow a very narrow safe path which restricted commercial growth.
The early years of the hunt for a solution were dominated on the one hand by greats such as Isaac Newton, John Flamsteed and Edmond Halley, and on the other hand, by numerous lesser players proposing theoretically ingenious but flawed and wildly impractical solutions, involving for example, anchoring fleets of ships at regular intervals across the ocean, which would fire signals at regular intervals so that passing vessels could measure their distance from land to east or west. Later on the race was a battle between the astronomers and the engineers, between those who saw the solution in the movements of the stars and planets and those who saw technology as the answer. In truth, both were partly right. The movements of celestial bodies had a part to play, but had in practice to be complemented by a mechanical device that could provide a practical and quick solution to the long standing problem. Step forward one of the unsung heroes of science and technology - John Harrison, master clockmaker, who rose from obscure and humble origins in Lincolnshire to become one of the great innovators of all time. He produced four progressively simpler and smaller timepieces, the last of which H-4 was the prototype for slightly later, smaller mass produced timepieces that in the hands of ships' captains were a contributory factor in the expansion of British sea power in the late 18th and early 19th centuries. His arch rival was the Rev Nevil Maskelyne, Astronomer Royal, a man not above changing the rules of the race to suit the astronomers vs. the mechanics. While Maskelyne behaved shabbily, he did make his own considerable contributions to lunar observations as part of the solution, and was responsible for establishing Greenwich as the prime meridian from which longitude would be measured across the world thereafter. But Harrison is the hero of this story, a pioneer who, in the author's words, "With his marine clocks, ... tested the waters of space-time. He succeeded, against all odds, in using the fourth—temporal—dimension to link points on the three-dimensional globe. He wrested the world’s whereabouts from the stars, and locked the secret in a pocket watch."
A good read, though some footnotes would be good and, even more so, a few diagrams and illustrations.