282 Experiments on Allanite. 
But the appearance ‘of the supposed oxide of iron in- 
duced me to suspect that it did not consist wholly of that 
metal. I thought it even conceivable, that the yttria which 
the mineral contained might have been rendered insoluble 
by the application of too much heat, and might have been 
concealed by.the iron with which it was mixed. A num- 
ber of experiments, which it is needless to specify, soon 
convinced me that, besides iron, there was likewise another 
substance present, which possessed properties different 
from any that I had been in the habit of examining. It 
possessed one property at least in common with yttria; its 
solution in acids had a sweet taste; but few of its other 
properties had any resemblance to those which the chemists 
to whom we are indebted for our knowledge of yttria have 
particularized. But as I had never myself made any ex- 
periments on yttria, I] was rather at a loss what conclusion 
to draw. From this uncertainty I was relieved by Mr. 
Allan, who bad the goodunegs to give mea small fragment 
of gadolinite, which had been received directly from Mr. 
Ekeberg. From this I extracted about 10 grains of yttria; 
and upon comparing its properties with those of the sub- 
stance in question, I found them quite different. Con- 
vinced by these experiments that the mineral contained no 
yttria, but that one of its constituents was a substance with 
which I was still unacquainted, I had recourse to the fol- 
lowing mode of analysis, in order to obtain this substance 
in a pure State. 
Il, Analysis of Allanite. 
1. 100 grains of the mineral, previously reduced to a 
fine powder, were digested in hot nitric acid till nothing 
more could be dissolved. The undissolved residue, which 
was silica, mixed with some scales of mica, weighed, after 
PeIne heated to redness, 35°4 grains. 
2. The nitric acid solution was transparent, and of a 
light-brown colour. When strongly concentrated by eva- 
poration, to get rid of the excess of acid, and set aside in 
an open capsule, it concreted into a whitish solid matter, 
consisting chiefly of soft crystals, nearly colourless, having 
ovly a slight tinge of yellow. These crystals being left 
exposed to the air became gradually moist, but did not 
speedily deliquesce. The whole was therefore dissolved in 
water, and the excess of acid, which was sull present, care- 
fully neutralized with ammonia. By this treatment, the 
solution acquired a much deeper brown colour; but still 
continued transparent. Succinate of ammonia was then 
dropped 
