Intelligence and Miscellaneous Articles. 537 



Protosmiamate of Mercury forms a bright yellow precipitate ; it is 

 not crystalline, and is insoluble in water ; the perosmiamate of mer- 

 cury forms prismatic crystals. 



Osmiamate of Silver is obtained directly by dissolving osmic acid 

 in an ammoniacal solution of a salt of silver, and afterwards super- 

 saturating with nitric acid. It may also be obtained by adding to a 

 solution of osmic acid in ammonia nitric acid in excess at first, and 

 then a salt of silver. It may also be prepared by double decompo- 

 sition with the salts of silver and soluble osmiamates, 



Osmiamate of silver is a crystalline powder of a lemon-yellow 

 colour ; it is very slightly soluble in water and in cold nitric acid, 

 more soluble in ammonia, and may be combined with it. It may be 

 dried in the dark without blackening, in vacuo, over sulphuric acid ; 

 eventually, however, it suffers decomposition, and then gives out 

 osmic acid ; at 176° F. it decomposes suddenly and with violent de- 

 tonation ; it is also decomposed by percussion, and likewise when 

 sulphuretted hydrogen is passed over the dried salt ; nitric acid de- 

 composes it readily when heated ; the liquor first acquires a brown 

 tint, and gradually becomes colourless with the disengagement of 

 osmic acid. 



This salt yields by analysis — 



Oxide of silver .. 32-08 32*060 32-13 



Osmium 55-011 



M. Gerhardt gives as its formula 0S03N(Ag). — Journ. de Ph. et de 

 Ch., Octobre 1847. 



ON SULPHATO-CHLORIDE OF COPPER, — A NEW MINERAL. 

 BY ARTHUR CONNELL, ESQ. 



This mineral occurs in small but very beautiful fibrous crystals, of 

 a fine blue colour, which is pale when the fibres are delicate, but 

 much deeper when they become somewhat thicker. Their form, 

 according to Mr. Brooke, is a hexagonal prism with the edges re- 

 placed, thus belonging to the rhombohedral system. They possess 

 considerable translucency, and have a vitreous lustre. On account 

 of the small quantity which he possessed, Mr. Connell was unable 

 to state the specific gravity, hardness, or fracture. Their locality is 

 Cornwall. Mr. Brooke is aware of the existence of only a very few 

 specimens of the mineral : one is in the British Museum. 



Like atacamite, this mineral colours the blowpipe flame as well 

 as the simple flame of a candle, of a fine greenish-blue, indicating the 

 presence of chloride of copper. Reduced to powder, and mixed in 

 sufficient quantity with charcoal powder, and then heated in a close 

 tube, it gives decided, although not strongly marked, indications of 

 the presence of sulphuric [sulphurous ?] acid by the smell, and 

 partial bleaching of Brazil wood paper, the remainder of the paper 

 being reddened, doubtless by muriatic acid vapours. Alone, in the 

 close tube, it yields a little water, and other appearances resembling 

 those afforded by atacamite. Heated alone on charcoal before the 

 blowpipe, it decrepitates strongly ; but when previously deprived 



