356 



PROFESSOR HEDDLE ON 



On 1*3 grammes — 



Silica, 







. 



, 



•543 



from Alumina, "019 



•562 = 43-23 



Alumina, . 23-09 



Ferric Oxide, . 













6-675 



Ferrous Oxide, 













1-131 



Manganous Oxide, 













•138 



Lime, 













20-003 



Magnesia, 













•884 



Potash, 













•962 



Soda, 













•935 



Lithia, 













•253 



Water, . 













2-4 



99701 



Insoluble silica, 1*957 per cent. 



This result is by no means a satisfactory agreement with the composition of 

 epidote. 



ZOISITE. 



1. This mineral was first found by me in Britain in Glen Urquhart. Inverness-shire. 

 It occurred in the most southerly of the limestone quarries, about a mile north-east of 

 Milltown. It was found only in one large nodule of calcite of about a hundredweight, 

 crystals of a grey to a pale bluish-white colour, about one inch in length, interlaced in 

 the calcite. There was a very little quartz ; a few specks of chalcopyrite and brushes 

 of light green actinolite in association with the mineral. 



The crystals, and indeed the mineral, has the general appearance of tremolite, but 

 the cleavage leaves no room for doubt. The form is well seen in these crystals, 

 but there are no terminations. The cleavage face seems a, twin face, as there are 

 repeated re-entering angles which produce a coarse striation. The crystals are brittle. 

 The cleavage face is somewhat pearly; fractures are vitreous. The specific gravity 

 taken on three pieces gave 3 "004, 3-111, and 3-014. 



On T303 grammes — 



Silica, 



in filter, 



from Alumina, .... 



Alumina, 



Carry forward, 



•484 





019 





•013 





•516 = 



= 39-60 





31083 





70-683 





