On the Occurrence of Gallium in Clay -ironstone. 397 



The precipitates of Phosphates and basic acetates D, E, and G. 

 Precipitate E. 



Chromium 5206 4289'0 4274'0 4253'0 



3606 3594 3579*0 



Gallium strong 4171'6and 4032'7 



(the latter somewhat weaker). 



Calcium weak 4226'8 



Potassium strong 4047'0 4043'5 



Sodium strong 5893'0, faint 5635, and 3303'0 



Precipitate D, 



The chromium line 5206 did not appear in the spectrum of this 

 precipitate. Both the gallium lines were very distinct, 4171*6 and 

 4032-7. 



It is remarkable how very generally the spectrum of potassium 

 appears along with that of the precipitated substances, whether 

 metals or basic acetates. 



Precipitate of basic acetates, G. 



This contained iron, chromium, lead, gallium, potassium, ami 

 sodium. The lines were those which have already been particu- 

 larised. 



The Residue left by Zinc, H. This was heated with aqua regia, 

 when all but a very small quantity of silica with a trace of a metallic 

 oxide dissolved. The liquid was filtered and the filtrate evaporated 

 with excess of hydrochloric acid to remove nitric acid. It was 

 diluted with water, when it showed a green colour. 



It was saturated with sulphuretted hydrogen and filtered to 

 separate the precipitate. The precipitate was partially soluble in 

 sodium hydrogen sulphide, yielding a sherry-coloured solution ; the 

 constituent causing. this colour was not identified, the quantity 

 present being very small. The residue, insoluble in alkaline 

 sulphide, contained copper and a. trace of lead, but no mercury, 

 bismuth,' or cadmium. 



The filtrate from zinc and precipitated metals J, was diluted and 

 heated to boiling. It gave a precipitate, and therefore ammonium 

 acetate was added to the hot liquid, and after boiling for several 

 minutes it was filtered. The filtrate became turbid immediately ; it 

 was then boiled and more ammonium acetate added and then filtered ; 

 the filtrate again became turbid. 



This precipitate was filtered off and heated in the oxyhydrogen 

 flame. 



It contained no gallium, but the spectrum gave lines of iron, 

 copper, sodium, potassium, and a .trace of lead. 



It is evident that all the gallium was extracted by the repeated 

 additions of ammonium acetate solution and boiling. 



