Ford has beaten General Motors for the first time in nearly a century, in terms of number of US factory workers. Ford has 50,703 to GM's 50,300 or so.
Answers. Well, the simplest answer is that the astrolabe pretty well had to be used at night and could not be used in bad weather. The compass, which relys on the magnetic field of the Earth rather than a visualiztion of the stars, works at any time, and in any weather.
Declination varies from place to place because the Earth's magnetic field is not uniform it dips and undulates. These local disturbances in the field can cause a compass needle to point away from both the geographic North Pole and the magnetic North Pole.ecause the Earth's magnetic North Pole attracts the north ends of other magnets, it is technically the South Pole of our planet's magnetic field. True north. While a compass is a great tool for navigation, it doesn't always point exactly north.