278 POPULAR LECTURES AND ADDRESSES. 



Europe, it had certainly become the practical 

 method, both for land and sea compasses, long 

 before Gilbert's time. In 1576 we find Robert 

 Norman, an instrument-maker, balancing his 

 needles and fly-card on a point, before the needles 

 were magnetized ; then magnetizing the needles, 



and finding the card to balance, not in its previous 

 horizontal position, but as represented in the dia- 

 gram, with a slope downwards towards the north : 

 and from this, being a philosopher as well as sailor 

 and instrument-maker, he went on to the important 

 scientific discovery of the dip. As for the 

 mariner's compass, differing from the compass 



