hillebband.] RARE EARTHS OTHER THAN ZIRCONIA. 77 
sulphates with a large excess (50 percent) of acetic acid. The method 
has been from time to time recommended, but without any data show- 
ing its value. The single separation made by Streit and Franz was 
far from perfect. 
Davis 1 separated zirconium sharply from aluminum, but not from 
iron, by precipitation as an oxyiodate in a boiling neutralized solution 
of chlorides, but the method is hardly applicable for rock analysis. 
Baskerville 8 has proposed a method for the separation of zirconium 
from iron and aluminum similar to his method for the separation of 
titanium from those elements (p. 73). It is based on the precipitability 
of Zr0 2 b}^ boiling the neutralized chloride solution for two minutes in 
presence of sulphurous acid, and seems to be excellent. As titanium is 
always present and is presumably quantitatively thrown down also, the 
two would have to be separated by hydrogen peroxide. No tests as to 
the availability of the method for separating the small amounts met 
with in rock analysis have been made. 
XV. RARE EARTHS OTHER THAN ZIRCONIA. 
For the few cases in which it may be necessary to look for rare earths 
other than zirconia, the following procedure is suggested as likely to 
prove satisfactory. 
The rock powder is thoroughly decomposed b} r several partial evapo- 
rations with hydrofluoric acid, the fluorides of all earth metals except 
zirconium are collected on a platinum cone, washed with water acidu- 
lated by hydrofluoric acid, and the precipitate washed back into the 
dish or crucible and evaporated with enough sulphuric acid to expel 
all fluorine. The filter is burned and added. By careful heating the 
excess of sulphuric acid is removed and the sulphates are taken up by 
dilute hydrochloric acid. The rare earths, with perhaps some alumina, 
are then separated by ammonia, washed, redissolved in hydrochloric 
acid, and evaporated to dryness, then taken up with water and a drop 
of hydrochloric acid, and only enough ammonium acetate to neutralize 
the latter added, followed by oxalic acid (not ammonium oxalate, which 
would fail to precipitate thorium). In this way as little as 0.03 per cent 
of rare earths have been found when working on not more than 2 grams 
of materials. 
This method eliminates at once most of the aluminum, all the iron, 
phosphorus, titanium, and zirconium, and has the further advantage of 
collecting with the earthy fluorides, as UF 4 , any uranous uranium that 
the rock might have held. 
An alternative method would be to fuse with sodium carbonate, leach 
with water to get rid of phosphorus as far as possible, dissolve the 
i Am. Chera. Jour., Vol. XI, p. 27, 1889. 
2 Jour. Am.Chem.Soc.,Vol.XVI,p.475,1891; Chemica] News, Vol. LXX,p.67, L894 
