With the right instruments and calculations, latitude is fairly easy to determine from the position of the sun and stars; people have been doing that for millennia. Longitude from Dava Sobel is a fascinating account of how a virtually unknown watchmaker named John Harrison conquered one of the oldest and thorniest problems surrounding the ocean voyages - the problem of accurately measuring longitude -, which stumped even the best of scientific minds for centuries.

But prior to the eighteenth century clocks didn’t work reliably in the rough environment of ships at sea, so the London clock would be off.To access your ebook(s) after purchasing, you can download the free Glose app or read instantly on your browser by logging into Glose. He accomplished what Newton had feared was impossible: He invented a clock that would carry the true time from the home port, like an eternal flame, to any remote corner of the world. By 1760 the board was considering a complicated but effective method of calculating a ship’s longitude from the positions of the moon and stars. Much like our skill at flinging sophisticated pieces of technology into orbit has advanced, so too has our ability to construct watches.

By the mid-18th century, one Board member -- the astronomer royal Reverend Nevil Maskelyne -- keenly wanted a solution that reflected his scientific discipline. He undertook the challenge and had the rest of his life ahead of him to devote to the problem, which he did. me, and the which had like to have occasioned me to become rough too; but however we got the ice broke . If you consider yourself a history buff, sailor, or horology head and you haven’t read Longitude, you owe it to yourself to get a copy.Navigational accuracy was paramount, yet the elusive concept of determining longitude plagued sailors and explorers, leading to countless shipwrecks and lost lives. Therefore, a new breed of fleet must be dispatched and anchored at 600-mile intervals in the oceans shooting cannons in the air. The central conflict of Longitude is not the need to calculate longitude but the antagonistic relationship between the Harrisons and the Reverend Maskelyne. Cannon reports or other very loud noises, intentionally sounded at certain times from known reference points, could fill the oceans with audible landmarks.

At the same time another less known figure; a skilled watchmaker from Lincolnshire named John Harrison who was stimulated by the scientific and the monetary factors surrounding this riddle decided to find a solution of his own.Background: Latitude lines are the parallel lines that circle the globe above and below the equator, and any sailor could figure out his latitude by measuring the length of the day or looking at the angle of the sun or the north star. There are a few more examples of how ships lost their way and wrecked or lost crew to scurvy because they were unable to get their own coordinates. If enough signal boats, therefore, were stationed at strategic points from sea to sea, sailors could gauge their distance from these stationary gun ships by comparing the known time of the expected signal to the actual shipboard time when the signal was heard. Lavishly produced with over 200 illustrations, The Illustrated Longitude has much new material to help the reader learn more of John Harrison’s extraordinary story and his times. It seems odd that she never addresses what appears to me the reason most people won’t have heard of Harrison: in the sciences we tend to lionize those who came up with big ideas, rather than the hands-on technicians who made them work.