The chronometer

Well firstly you should know that the chronometer is usualy used with others instruments, in fact alone the chronometer is quite useless. So the navigator has to use three instruments, firstly the compass to find his cape (the direction or the angle of his boat). Thanks to this cape he know his direction from his departure. Know he can move. That's at this moment he needs to measure his speed. There is much kind of instruments which allows the navigaor to measure this speed as the Tachymetre. Now the last data he needs is the precise hour. Our chronometer is used here. Thanks to his cape, his speed and the time the navigator can calulate his position from the place he came from. That's how the Chronometor is used to find our position.