356 plikt's natural histort. [Book XXXYl. 



on Macedonia, and lies to the right of the road which leads from 

 the town of Boebe to lolcos ; a third, from Hyettus in Boeotia ; 

 a fourth, from Alexandria in Troas ; and a fifth, from Magnesia 

 in Asia. The leading distinction in magnets is the sex, male 

 and female,-^ and the next great difference in them is the 

 colour. Those of Magnesia, bordering on Macedonia, are of 

 a reddish black ; those of Boeotia are more red than black ; and 

 the kind that is found in Troas is black, of the female sex, 

 and consequently destitute of attractive power. The most 

 inferior, however, of all, are those of Magnesia in Asia : they 

 are white, have no attractive influence on iron, and resemble 

 pumice in appearance. It has been found by experience, that 

 the more nearly the magnet approaches to an azure colour, 

 the better it is in quality. The Ethiopian magnet is looked 

 upon as the best of all, and is purchased at its weight in silver: 

 Zmiris in Ethiopia is the place where it is found, such being 

 the name of a region there, covered with sand. 



In the same country, too, the magnet called '' hsematites"-* is 

 found, a stone of a blood-red colour, and which, when bruised, 

 yields a tint like that of blood, as also of saffron. The 

 hasmatites has not the same property^^ of attracting iron that 

 the ordinary magnet has. The Ethiopian magnet is recog- 

 nized by this peculiarity, that it has the property, also, of 

 attracting other magnets to ik^^ All these minerals are use- 

 ful as ingredients in ophthalmic preparations, in certain propor- 

 tions according to the nature of each : they are particularly 

 good, too, for aiTesting defluxions of the eyes. Triturated in 

 a calcined state, they have a healing effect upon burns. 



In Ethiopia, too, not far from Zmiris, there is a mountain 

 in which the stone called *' theamedes"-^ is found, a mineral 



2* An absurd distinction, as Ajasson remarks ; based, probably, on East- 

 ern notions, and with reference to the comparative powers of attraction. 



25 From a't/ia, "blood." He alludes to Specular iion, red ochre, or 

 red hematite, another oxide of iron. 



'-^6 Sometimes it has, but in a very slif^ht degree. 



27 Ajasson remarks that most probably the possessors of this pretended 

 variety knew the distinction between the two poles of the magnet, and 

 took care, when it was their interest to do so, to place the opposite pole to- 

 wards that of the other loadstone. 



2» It was the belief of the Duke of Noya Caraffa, that this stone was identi- 

 cal with Toui-maline : but, as Beckmann says, tourmaline, when heated, lirst 

 attracts iron, and then jrepels it. Hist. Inv. Vol. I. pp. 87, 88. Bohn's Edi- 

 tion. Ajasson is of opinion that the Theamedes was neither more nor less 



