522 THE APPLICATIONS OF PHYSICAL FORCES. [BOOK v. 



makes with the meridian of the place it is in. In sailing by reckon- 

 ing, the other element, determined by means of the instrument called 

 the loy, is the speed of the ship. 



Fie. :-*35. Gamliey's declination compass. 



The compass thus used is spoken of by sailors as the ship's com- 

 pass. It is fixed abaft near the wheel, in a sort of protecting box 

 called the binnacle. The binnacle is generally divided into three 

 compartments, one in the middle containing a lamp for taking 



