Chap. 20.] Molyldena. 125 



acid, heated with fulphur in a particular manner, is 

 capable of being converted into a fubftance in every 

 refpect the fame as native molybdena. 



This mineral is fcarce. It is diftinguimed from black 

 lead by a more mining, fcaly appearance -, and it marks 

 paper with a more brilliant ftroke. 



