On the Occurrence of Gallium in Clay -ironstone. 395 



being collected. The mother liquor from the last crop of crystals 

 was evaporated almost to dryness to expel acid, and, after addition 

 of water, rods of zinc were immersed in the solution, which was 

 then left undisturbed for forty-eight hours. The zinc was found to 

 have been almost all dissolved. The precipitated metals and the 

 residue of zinc were washed and dried. Residue H. The filtrate, 

 after three precipitations with ammonium acetate, was mixed with 

 the mother liquor of the ferrous chloride crystals from the first 

 portion, so that the liquid then represented the whole of the ingot. 

 It was diluted, mixed with an excess of ammonia and ammonium 

 sulphide, to precipitate all the iron and metals of that group still in 

 the solution, and filtered. The filtrate was evaporated to dryness and 

 gently ignited to expel ammonium salts. A residue was left, which 

 contained the alkaline earths and alkaline metals. 



The Spectrographic Analysis of the Residues and of the Precipitates. 



From the foregoing description it will be observed that by partial 

 solution the metals precipitable by iron may be looked for along with 

 carbon, and, probably, some phosphides of iron and other metals. 

 Such phosphides yield the flame spectra of the metals only, and not 

 of the phosphorus combined with them. Precipitation with zinc in 

 an acid solution was expected to give a deposit (F and JET) which 

 would yield the spectra of copper, silver, bismuth, lead, thallium, and 

 tin in the oxyh) drogen flame, if these metals were not already pre- 

 cipitated by the iron, and present in the residues A and B while 

 D, E, and G are compounds which fall under the category of sesqui- 

 oxide metals, including beryllium, aluminium, indium, gallium, and 

 chromium. Of these, aluminium and beryllium were expected to 

 show no spectra in the oxyhydrogen flame, and for these it was 

 intended to use spark spectra. 



The residue A, when dried in the water oven and gently heated, 

 gave off fumes which indicated that an oil was present, and extrac- 

 tion with ether and subsequent evaporation did, indeed, yield a 

 quantity of a brown oil. 



The oxyhydrogen flame spectra of the substances separated were 

 photographed, and the following are particulars regarding their 

 spectra. 



The insoluble residue A contained iron, manganese, copper, gallium, 

 sodium, chromium, silver, and nickel. 



The lines which served to identify the metals had the following 

 wave-lengths : 



Iron .... 4308-0 4046'0 3929'8 3922-0 3904-8 



3898-5 3886-5 3860-0 3857'0 3841-0 

 3834-0 3826-0 3824-5 3758-4 



2 H 2 



