286 Experiments on Allanite. 
felt gritty between the teeth, and was easily reduced to 
powder. It effervesced in sulphuric, nitric, muriatic, and 
acetic acids, and a solution of it was effected in each by 
means of heat, though not without considerable difficulty. 
The solutions had -ari austere and slightly sweetish taste. 
When examined by re-agents, they exhibited the following 
properties: 
(1.) Prussiate of potash. A white precipitate. 
(2.) Oxalate of ammonia. <A white precipitate. 
(3.) Tartrate of potash. A white precipitate. 
(4.) Hydro-sulphuret of potash. A white precipitate. 
(5) Phosphate of soda. A white precipitate. 
(6.) Arseniate of potash. A white precipitate. 
(7.) Potash and its carbonate. A white precipitate. 
(8.) Carbonate of ammonia. A white precipitate. 
(9.) Ammonia. <A white gelatinous precipitate. 
(10.) A plate of zinc. No change. 
These properties indicated oxide of cerium. IT was there 
fore disposed to consider Ithe substance which I had ob- 
tained as oxide of cerium. But on perusing the accounts 
of that substance, given by the celebrated chemists -to 
whose labours we are indebted for our knowledge of it, 
there were several circumstances of ambiguity which oc- 
curred. My powder was dissolved in acids with much 
greater difficulty than appeared to be the case with oxide of 
cerium. ‘Lhe colour of my oxide, when obtained from 
oxalate by exposing it to a red heat, was much lighter, 
and more inclined to yellow, than the oxide of cerium. 
In this uncertainty, Dr. Wollaston, to whom T commu- 
nicated my difficulties, offered to send me down a specimen 
of the mineral called cerite, that I might extract from 
it real oxide of cerium, and compare my oxide with it, 
This offer I thankfully accepted *; and upon comparing 
the properties of my oxide with those of oxide of cerium 
extracted from cerite, I was fully satisfied that they 
were identical. The more difficult solubility of mine was 
owing to the method I bad employed to procure ity and to 
. 
* The specimen of cerite which I analysed, was so much mixed with 
actinolite, that the statement of the results which I obtained cannot be of 
much importance. The specific gravity of the specimen was 4149. I 
found it composed as follows: 
A white powder. left by muriatic acid, and presumed to be silica 47-3 
Red oxide of cerium - - a Z E Ls « behndas 
Troa - - 7 = a tS us a % : Pi As 
Volatile matter - - - m a = 5 <! 3 
Loss - - 2 - 5 2 f Pe a 2 3 V7 
100'0 
the 
