Longitude, or rather the “starting point” for lines of longitude, is entirely arbitrary. But how far away were you from the nearest charted island? And were you to the east of it, or the west? So you could figure out how far away from the equator or the poles. Latitude corresponds both to the sun’s altitude in the sky (at noon) and to the altitude of certain stars (if you are in the Northern Hemisphere, Polaris is a good choice) at night. Latitude was relatively easy-well, easy enough once you dealt with the pitching deck, the storms, and the scurvy. I’m not sure how to describe how lost you could be, out there on the ocean, no longer in sight of shore.

In the days-centuries-prior to GPS, you could get lost. GPS might not be great at giving directions, but that doesn’t mean you’re lost. Thanks to GPS, we can forget that calculating longitude without the help of a network of satellites is difficult and requires great mathematical and engineering expertise. I don’t use it that much personally, because I don’t tend to go anywhere, but I’m sure all this technology I love to use makes use of GPS. Includes an eight page center section of color photographs.I take GPS for granted. Remember all you need to know about navigation is that latitude tells you where you are lost at and longitude tells you how long you have been lost.

Full of heroism and chicanery, it is also a fascinating brief history of astronomy, navigation, and clockmaking, and opens a new window on our world. This book is the dramatic human story of an epic scientific quest and of Harrison's forty-year obsession with building his perfect timekeeper, known today as the chronometer. One man, John Harrison, in complete opposition to the scientific community, dared to imagine a mechanical solution-a clock that would keep precise time at sea, something no clock had ever been able to do on land.

Thousands of lives and the increasing fortunes of nations hung on a resolution. Lacking the ability to measure their longitude, sailors throughout the great ages of exploration had been literally lost at sea as soon as they lost sight of land. Anyone alive in the eighteenth century would have known that the longitude problem was the thorniest scientific dilemma of the day-and had been for centuries. A tight mass market book with jacket like flaps. Vaccaro, Claire Naylong - Book Design (illustrator).

Longitude dava