THE DETECTION AND WIDE DISTRIBUTION OF YTTRIUM. 
911 
corroborates Professor Roscoe’s conclusions,* that Delafontaine’s philippia is nothing 
but a mixture of yttria and terbia. 
Mosandra. 
62. The chemical characters of this earth are so little known that I could not 
attempt to search for it. But as the citron band-forming earth always appeared 
concentrated amongst those whose double sulphates were most soluble in potassic 
sulphate,—and, of these, amongst those having the palest colour and lowest atomic 
weight,—it was scarcely conceivable that the earth I v/as in search of should 
ultimately prove to be one whose properties did not in any case correspond to these,— 
of a dark orange yellow colour, forming a difficultly soluble double potassic sulphate, 
and having the very high equivalent of M = 51'2 ; these being the properties ascribed 
to mosandra by the discoverer, Professor Lawrence Smith. 
Separation of terbia and yttria from erbia , holmia , and thulia. 
63. The mother-liquors, from which as much terbic formate as possible had been 
separated by the process above described (56, 57), were now evaporated down with 
nitric acid till all the formates were decomposed, and the highly acid solutions of 
nitrates were fractionally precipitated with oxalic acid (51, 52, 53). 
64. The erbic, holmic, and thulic oxalates come down first; then the terbic 
oxalate ; lastly the yttric oxalate (53). After repeated fractional precipitations I at 
last succeeded in obtaining a mixture of yttria and terbia of a golden colour, which 
gave a very brilliant phosphorescent spectrum in the radiant matter tube, but showed 
no trace of absorption band when the concentrated solution of the nitrates was 
examined in the spectroscope. 
Separation of terbia and yttria. 
65. The crude yttria was now added to the mixture of earths (54) having a hydrogen 
equivalent M= 33, and the whole submitted again to fractionation with oxalic acid, in 
a somewhat modified manner. 
An excess of strong nitric acid was added to the solution of mixed terbic and yttric 
nitrates, and the solution was heated to the boiling point. Strong oxalic acid solution 
was added drop by drop till a faint permanent precipitate was produced. Strong nitric 
acid was now added, a drop at a time, till the solution again became clear, and the 
whole was allowed to cool very slowly without agitation. On cooling, an oxalate 
crystallised out in brilliant prisms. These contained nearly all the terbia with some 
of the yttria, whilst the mother-liquor contained most of the yttria with a little terbia. 
The filtrate was treated with more oxalic acid, a fresh crop of crystals being produced, 
* ‘ Jour. Chem. Soc.,’ vol. 41, p. 277. 
6 A 2 
