TERRESTRIAL MAGNETISM, ETC. 281 



" vails in the cities of the Mediterranean, in Sicily, 

 " Genoa, and the Venetian Republic. In all those 

 " places the magnetic iron is attached to the fly- 

 " card with its length parallel to the diameter, 

 " through the rose or lily, so that at any place 

 " where there is no variation the true north and 

 " south points are shown by this diameter of the 

 " circle ; and where there is variation the amount 

 " is shown by the deviation of the point marked 

 " by the lily on the card from the true north. A 

 " second prevails in Dantzic, throughout the Baltic 

 " Sea, and in the Belgian provinces. In it the 

 " needles are fixed three-quarters of a point to the 

 " east of the lily. In Russia the difference 

 " adopted is two-thirds of a point. Lastly, com- 

 " passes which are made in Seville, Lisbon, 

 " ' Rupella/ Bordeaux, Rouen, and anywhere in 

 " England, have an interval of half a point between 

 " the lily and the direction of the needles. 



" From those differences have grown up great 

 " errors in nautical management and marine 

 " science. For when the directional positions of 

 " maritime places (as promontories, ports, islands) 



