CH. viii. FLAVIO GIOJA MARINER'S COMPASS. 53 



people will make machines to fly in the air. This shows 

 that he must have imagined many things which were not 

 really discovered till more than 300 years afterwards ; but 

 they were all dreams which he could not carry out himself. 

 Before 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, 1300. 

 About ten years after the death of Bacon, a man was born in 

 a little village called Amain, near Naples, who made a dis- 

 covery 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 discovered 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 loadstone attracted iron ; and 

 a piece of loadstone is called a magnet, from the Greek word 

 magnes, because it was supposed 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 



