+ 
380. On ALLANITE, a new 
temperature, whether thefe acids were concentrated 
or diluted. 
(16.) A plate of tin put into the nitric folution, occafioned no 
change. tad 
(17.) A portion being inclofed in a charcoal crucible, and ex- 
poted for an hour to the heat of a forge, was not re- 
duced to a metallic button, nor could any trace of it 
be detected when the crucible was examined. 
THESE properties were all that the fmall quantity of the 
matter in my pofleffion enabled me to afcertain. They une- 
quivocally point out a metallic oxide. Upon comparing them 
with the properties of all the metallic oxides known, none 
will be found with which this matter exactly agrees. Cerium 
is the metal, the oxides of which approach the neareft. The 
colour is nearly the fame, and both are precipitated white by 
pruffiate of potafh, fuccinate of ammonia, and benzoate of © 
potafh. But, in other refpedts, the two fubftances differ entire- 
ly. Oxide of cerium is precipitated white by oxalate of am- 
monia and tartrate of potafh; our oxide is not precipitated at 
all: Oxide of cerium is precipitated white by hydro-fulphuret 
of ammonia; while our oxide is precipitated black : Oxide of ce- 
rium is not precipitated by zinc, while our oxide is thrown 
down black. There are other différences between the two, 
but thofe which I have juft mentioned are the moft ftriking. 
THESE properties induced me to confider the fubftance 
which I had obtained from the Greenland mineral as the oxide 
of a metal hitherto unknown ; and I propofed to diftinguith it 
by the name of Junonium. 
In the experiments above detailed, I had expended almoft all 
the oxide of Junonzum which I had in my poffeflion, taking it for 
granted that I could eafily procure more of it from the Green- 
land 
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