338 Examination of a remarkable Red Sandstone. [No. 149. 



In the forceps — Fuses into a metallic looking slag at the edges. 

 With Soda on Charcoal. — Fuses with considerable ebullition, and a 

 part is reduced, giving bright white, and soft, metallic grains and streaks 

 in the mortar ; these dissolve quickly in nitric acid, but give no precipi- 

 tate with mur : acid. With prussiate of potass, dark blue precipitate 

 and are therefore iron. 



The powder of the washing before the Blowpipe, with Soda on Pla- 

 tinum Wire. — Fuses with effervescence into an opaque and dirty olive 

 green wrinkled bead, which in the reducing flame becomes speckled 

 with dark spots. With more soda the same. In the reducing flame 

 greyish. The bead allowed to deliquesce takes a bright olive (or grass) 

 green, and in the mortar gives metallic traces as before. 



Via humida. — Powder boiled in mur : acid, the red colour changes 

 to a dull yellow or dirty orange, with a white powder at bottom. 

 When cool and settled, the acid is of a clear yellow orange ; tested by 

 prussiate potass. Dark blue. 



Tinct. Galls. — A clear brown which by the addition of lime water, 

 becomes purple and black. 



Hydrosulph. Potass. — A dirty black brown. 



Hydrosulph. Ammonia. — The same. 



The solution filtered left a greyish white powder which was silex. 



The solution was evaporated, re-dissolved and precipitated by ben- 

 zoate of ammonia. The precipitate was of a light buff colour and the 

 solution left clear. This solution and the precipitate gave no trace of 

 titanium, but a little iron was found in it ; the benzoate of ammonia 

 not having, apparently, precipitated the whole of the oxide. 



For Iodine. — The powder heated gradually with concentrated sul- 

 phuric acid evolved no vapour, and before the blowpipe with microcosmic 

 salt and oxide of copper gave also no trace of Iodine. 



The sulphuric acid solution gave no trace but of iron. 



The cherty -looking Veins. — A vein giving both with the soft iron of a 

 knife and a steel edge-tool, a greenish metallic streak, was selected. 



A small triangular fragment fuses into a black slag at the apex, 

 the assay becoming black and iron-like. Fused with soda an olive colour- 

 ed bead, with borax clear pale-green glass, shewing only silica and iron. 



Result. — The rock is a red ferruginous sandstone, with pure silica in 

 grains, and protoxide of iron (Haematitic ?) in little black specks and 



