154 PROCEEDINGS OF SECTION B. 



Diallogite (cai-bonate of manganese and iron) occasionally 

 accompanies it with quax'tz in vughs, in the felstone. 



II. — Embolite prom Silverton. 



This was a massive specimen of the mineral, enclosed in a 

 siliceous and ferric oxide gangue, handed me by Professor 

 Liversidge. It contained, in addition to chlorine and bromine, 

 a trace of iodine. 



To obtain the chlorobromide free of impurity, several portions 

 were fused with sodium carbonate, and the sodium bromochloride 

 reconverted into the silver salt. 



The silver buttons obtained from these fusions were weighed 

 and percentage calculated. 



I. II. 



Silver 59.43 % 58.29 % 



From the difference in weight between the total chlorobromide 

 thus obtained, and the original weight of mineral taken for fusion, 

 the quantity of impurity was determined. 



Two determinations yielded — 



I. II. 



Impurity 7.75% 7.62% 



Various portions of the chlorobromide of silver prepared as above, 

 were fused in a bulb tube in a stream of dry chlorine gas, and 

 the resulting chlorides weighed, and fusions repeated until the 

 weights were constant. From the difference in weight between 

 the chlorobromide of silver taken, and weight obtained of silver 

 chloride, the amount of bi'omine and bromide of silver contained 

 was calculated. To check results, the chloride of silver in one 

 instance was reduced to metallic silver in a hydrogen stream, and 

 the resulting silver carefully weighed. 



Three determinations yielded — 



I. II. III. Mean. 



Chloride of silver... 66.39% 66.31% 66.19% 66.29% 

 Bromide of silver... 33.61% 33.69% 33.81% 33.70% 



ToaOO% 10000% 100.00% 99799% 



