CH. viii. FLA VIO GIOJA MARINERS COMPASS. 53 



though he does not tell us how he arrived at them. Be- 

 fore we leave Roger Bacon I must warn you not to con- 

 fuse him with Francis Bacon, Chancellor of England, who 

 was quite a different* man, and lived more than 200 years 

 later. 



Flavio Gioja discovers the Mariner's Compass, 

 130O. About ten years after the death of Bacon, a man 

 was born in a little village called Amain, near Naples, who 

 made a discovery of great value. The man's name was 

 Flavio Gioja, and the discovery was that of the mariner's 

 compass. Long before Flavio's time people knew that there 

 was a kind of stone to be found in the earth which attracted 

 iron. There is an old story that this stone was first dis- 

 covered by a shepherd, who, while resting, laid down his 

 iron shepherd's crook by his side on a hill, and when he 

 tried to lift it again it stuck to the rock. Although this 

 story is probably only a legend, yet it is certain that the 

 Greeks and most of the ancient nations knew that the load- 

 stone attracted iron ; and a piece of loadstone is called a 

 magnet^ from the Greek word magnes, because it was sup- 

 posed to have been first found at Magnesia, in Ionia. 



A piece of iron rubbed on a loadstone becomes itself a 

 magnet, and will attract other pieces of iron. But Flavio 

 Gioja discovered a new peculiarity in a piece of magnetised 

 iron, which led to his making the mariner's compass. He 

 found that if a needle or piece of iron which has been 

 magnetised is hung by its middle from a piece of light 

 string, it will always turn so that one end points to the 

 north and the other to the south. He therefore took a 

 piece of round card, and marking it with north, south, east, 

 and west, he fastened a magnetised needle upon it pointing 

 from N. to s. ; he then fastened the card on a piece of cork 

 and floated it in a basin of water. Whichever way he 



