356 T PHYSIOGRAPHY. CLASS II. 



these, the varieties discovered at successive periods, 

 were almost all united. Those found near Egra in Bohe- 

 mia, were, however, considered as a particular species, 

 and from their locality they received the name of Egerane, 

 while that of Vesuvian was retained for the other ; both 

 have been comprised under the name of Idocrase. The 

 only difference that seems to exist between these varieties 

 consists in the relative length of the crystals, which is 

 much greater in Egerane, and the crystals more deeply 

 streaked and altogether less perfectly formed, than those 

 of Vesuvian, which appear in shorter prisms, bounded by 

 a greater number of brilliant planes. The composition of 

 massive varieties is granular in the latter, and columnar in 

 the former. All the colours, however, of Vesuvian and 

 Egerane form a continuous series, in which no constant 

 limits can be fixed. A variety resembling Egerane has been 

 called Lobdile, and Frugardlte ; another from Tellemarken 

 in Norway, of a blue colour, and containing copper, which 

 is supposed to belong to the present species, has been 

 termed Cyprine. 



2. Pyramidal Garnet has yielded by analysis the follow- 

 ing results : the two first were obtained by KLAPROTH, 

 the third by Count DUN IN BORKOWSKY. 



Vesuvian, Vesuvian, Egerane, 



from Vesuvius. from Siberia. from Bohemia. 



41-00. 

 22-00. 

 22-00. 

 3-00. 

 6-00. 

 2-00. 

 1-00. 



The varieties from Vesuvius and from Fassa in the Tyrol, 

 easily melt into a dark coloured globule, which is pale 

 green in Egerane, and the formation of it accompanied 

 with effervescence. The blueish-grey eight-sided prisms, 

 formed in the iron-slag from Merthyr Tydvil, are consider. 



