To expand search, see The Reckoning of Time. Laterally related topics: The Sundial and The Calendar.
The Mathematics and the Liberal Arts pages are intended to be a resource for student research projects and for teachers interested in using the history of mathematics in their courses. Many pages focus on ethnomathematics and in the connections between mathematics and other disciplines. The notes in these pages are intended as much to evoke ideas as to indicate what the books and articles are about. They are not intended as reviews. However, some items have been reviewed in Mathematical Reviews, published by The American Mathematical Society. When the mathematical review (MR) number and reviewer are known to the author of these pages, they are given as part of the bibliographic citation. Subscribing institutions can access the more recent MR reviews online through MathSciNet.
Proverbio, Edoardo. The contribution of the mechanical clock to the improvement of navigation. Longitude zero 1884--1984 (Greenwich, 1984). Vistas Astronom. 28 (1985), no. 1-2, 95--103. SC: 01A99, MR: 809 625.
It is a relatively simple matter to measure latitude with simple instruments; your latitude is for example nearly equal to the altitude of the pole star above your horizon. Longitude can in theory be determined by what amounts to determining your time zone; this can be determined by noting the time of sunrise. If you note that the sun rises three hours later than it did at home, you would expect to be about 3 time zones, or 45 degrees to the west of home. However, until the mid 1700s, there was no accurate way to keep track of time at sea; traditional methods such as water clocks were hopeless on a moving ship. A solution was proposed by the mathematician and astronomer Galileo, who discovered the moons of Jupiter. These moons occasionally eclipse each other, and if one could predict when that would happen, one would in effect have a clock in the sky. Other mathematical/astronomical methods were proposed as well; in theory if you have accurate enough predictions of the orbit of the moon, you can predict time by observations of the moon as well. Unfortunately, mathematical methods were not yet adequate to predict the positions of astronomical objects with enough accuracy, and the computations could have been difficult for the average sailor in any case. So attention began to focus again on finding a more accurate clock. Some of the problems in clock design involved mathematics as well. For example, it was known that a pendulum will swing in roughly equal time regardless of the size of the swing. (A famous story tells of how Galileo discovered this in church one day, by comparing with his pulse.) "Roughly equal" wasn't good enough, and a mathematically very interesting solution was suggested by the mathematician and scientist Christiaan Huygens. His suggestion involved improving the accuracy of the pendulum by using the tautochrone property of the cycloid. Huygens tried a number of other things as well. Of course, there is much more that doesn't involve mathematics so directly. A fascinating article. Closely related topics: Navigation, The Reckoning of Time, Astronomy, Galileo Galilei, Christiaan Huygens, and The Cycloid.