242 POPULAR LECTURES AND ADDRESSES. 



physical science to purposes of great practical 

 utility to mankind. (It is worthy of remark, in 

 passing, that there are just two other practical 

 applications of electro-magnetic science extensively 

 in use at the present day the electric telegraph 

 and electro-plating. These two upstarts, neither 

 of them fifty years old, are both to-day familiar in 

 every British household, while the venerable old 

 mariner's compass, popular as it is in name, is not 

 much more popularly known, in reality, now, than 

 when Guiot of Provence described it six hundred 

 years ago as pointing to "the star," or when 

 Shakespeare made " lode-star " a symbol of attrac- 

 tion.) But when I tried to write on the mariner's 

 compass, I found that I did not know nearly 

 enough about it. So I had to learn my subject. 

 I have been learning it these five years, and still 

 feel insufficiently prepared to enlighten the readers 

 of Good Words upon it when I now resume the 

 attempt to complete my old article. 



In the slight historical sketch of the mariner's 

 compass which appeared in Good Words it was 

 pointed out that Dr. Gilbert, of Colchester, 



