78 Intelligence and Miscellaneous Articles. 



perfect crystals, which are brilliant, and of a pale olive-green colour, 

 and have the appearance of chloride of silver. This specimen was 

 very rich, for it yielded 0*0688 of silver, and contained 0*45 of car- 

 bonate of lead, which, intimately mixed with quartz and a little 

 oxide of iron, formed the principal portion of the mass. 



M. Berthier has also found tliis mineral among the silver ores of 

 Huelgoeth, department of Finistere in France. Two specimens 

 were obtained by him : the first of these is described as being 

 porous or scoriform, containing white quartz imbedded in foliated 

 hydrate of iron. On the edges of the foliated iron ore the naked eye 

 could distinguish small cubic grains of a pearl-white colour, which 

 had all the characters of chloride of silver. 



The second specimen had the appearance of compact oxide of Iron, 

 containing here and there milk-white quartz ; it was throughout im- 

 pregnated with chloride of silver, which occasionally appeared in the 

 form of very small brilliant crystals. To analyse this mineral, 10 

 grammes were first treated with ammonia and heat to dissolve the 

 chloride of silver, and afterwards by boIHng hydrochloric acid to dis- 

 solve the oxide of iron ; this acid also dissolved a certain portion of 

 lead, which probably was in the state of phosphate. The quartzose 

 residue weighed 3"26 grammes ; it contained 0"17 gramme of silver, 

 which must have been in the metallic state : the ammoniacal solu- 

 tion gave by boiling and saturation with nitric acid, 1"84 gramme of 

 chloride of silver, which, supposing it to be pure, contained r40 

 gramme of silver, which, added to 0"17 gramme remaining in the 

 quartz, gives a total of r57 gramme; a result which differed so 

 very little from that obtained by assaying, as to prove the absence 

 of bromide of silver, and that this was the case was confirmed by 

 additional experiments. 



After this a third specimen was received from Huelgoeth ; it was 

 very small, but as rich as the foregoing, and in It there were distin- 

 guishable, besides granular cubic crystals of chloride of silver, other 

 grains of an olive-green colour, which had exactly the same appear- 

 ance as the bromide of Plateros, and the following experiments proved 

 the presence of this substance. 



Five grammes of the pulverized mineral were boiled in a solution 

 of oxalic acid, until the oxide of iron was perfectly dissolved : the 

 residue weighed about a gramme, and it evidently contained a mix- 

 ture of canary-yellow and white grains. It was digested in hot 

 solution of ammonia until all the yellow powder disappeared ; it re- 

 quired a large quantity of the alkali for this purpose, which would 

 not have been the case to dissolve pure chloride. The solution was 

 gradually saturated with nitric acid, and it was observed that the 

 successive deposits formed had an evident yellow tint, but gradually 

 diminishing in Intensity, except the last, which were white. The 

 yellow deposits were collected and examined In the following man- 

 ner : — A portion was treated with chlorine and sether ; the aether be- 

 came of a yellow colour. Another portion was dissolved In ammo- 

 nia, hydrosulphate of ammonia was added to the solution, and the 

 black precipitate formed was separated, and was found to be pure 



