262 



the different directions of the fibres and their lami- 

 use, and the nearer resemblance they bear to fractured 

 bones. 



The blue turquois, is indeed no other than fossil 

 bone, or ivory saturated with copper dissolved in 

 an alkaline menstruum ; the green turquois is the 

 same substance, intimately penetrated by a cupereous 

 matter dissolved in an acid menstruum. 



16. The Loadstone is found in iron mines, and 

 resembles iron both in weight and colour. Its most 

 remarkable properties are, turning to the poles, and 

 attracting iron. As to the former, when it move* 

 without hindrance, it constantly turns one end to the 

 north, the other to the south, only declining a little 

 to the east or west. If two loadstones are brought 

 within a certain distance of each other, that part of 

 one which is toward the north pole of the earth, re- 

 cedes from that part of the other which respects 

 the same pole. But it accedes to it, if the southern 

 pole of the one,be turned toward fc the southern pole of 

 the other. The* needle touched with the loadstone, 

 when on this side the equinoctial line, has its north 

 point hendirig downward, on the other side, its south 

 point ; under the line, it turns any way, and is of 

 no use. 



As to its attractive power, it net only sustains ano- 

 ther loadstone, (provided the north pole of the one 

 be opposed to the south pole of the other) but iron 

 also. Likewise if steel dust be laid upon a loadstone 

 it will so dispose itself, as to direct its particles strait 

 to the poles, whence they will be moved rornd by 

 Jittle and little, till they are parallel to the axis of 

 the loadstone. It communicates its virtue to iron, 

 and if it be armed with (that is, fixed in) iron, its 

 force is greatly increased. It loses its force either 

 by fire, or by letting two loadstones lie together, with 

 the north pole of one opposed to the north, or the 

 outh pole of one to the south of the other. These 



