TERRESTRIAL MAGNETISM, ETC. 283 



" the variation ; and he urges that there must be 

 " none by many geometrical demonstrations on 

 " foundations altogether vicious (on account of his 

 " small knowledge and experience of magnetic 

 " affairs). Likewise Peter of Medina, not admitting 

 " the existence of variation, has deformed the 

 " nautical art with many errors." 



The compass now in most common use at sea in 

 all classes of ships of all nations is substantially the 

 same as the compass made by Robert Norman 

 three hundred years ago, and described as above 

 by Gilbert. Happily now, however, all compasses 

 are made according to the original Italian plan of 

 marking the correct magnetic north direction by 

 the lily, and thus we are now quite free from the 

 gratuitous errors due to confusion as to the inten- 

 tion of the instrument-maker so deservedly con- 

 demned by Gilbert. 



The wooden bowl holds its place at the present 

 day, not only in a few coasters and fishing boats, but 

 in many old-fashioned sailing ships of high dignity. 

 For the Admiralty standard compasses and for com- 

 passes generally in merchant steamers, the bowls are 



