284 POPULAR LECTURES AND ADDRESSES. 



now made of copper or brass, instead of wood. The 

 lead weight and the gimbal-rings are in all com- 

 passes just as described by Gilbert. The two 

 varieties of needle which he describes the pointed 

 oval needle and the pair of thin bent needles with 

 their ends united made according to patterns 

 which have survived without material change for 

 at least three hundred years, are both still to be 

 found at sea, though they have generally given way 

 to safer and simpler forms recommended for the 

 British Navy forty years ago by a scientific com- 

 mittee appointed to examine the compasses then in 

 use, and to advise regarding improvements. Accord- 

 ing to the recommendation of this committee, the 

 compass of the British Navy and of well-found 

 merchant steamers has for its needles pairs of par- 

 allel straight bars of flat clock-spring fixed below 

 the card, with the breadth of the bar perpendicular 

 to the card, instead of coinciding with the under 

 surface of the card, as in the oval needles of the 

 older compasses. In the Admiralty standard com- 

 pass there are two pairs of needles ; in the compass 

 of merchant ships, hitherto generally, just one pair 



