+ * es 
Want of Identity between Microlite and Pyrochlore. 121 
A portion of the acid was fused with carbonate of potash ina 
platina crucible; water was boiled upon the mass, whereby a _ 
complete aitabiaas was effected. 'To a portion of the solution, hy- 
drochloric acid was added. It first occasioned a cloudiness, but 
penne emes the fluid became clear. The same effect was produ- 
ced by oxalic acid. Ferrocyanide of potassium afforded with the 
oxalic solution, a yellow precipitate, and the tincture of ae 
with the same, a rich orange precipitate. 
A portion of the acid was fused with biphosphate of node on 
a platina hook, in the inner flame of the blowpipe : a transparent 
glass was obtained, which was colorless while hot, as well as after 
cooling. Fused with soda before the blowpipe, an opake, white 
bead was obtained. 
~ My conclusion concerning the composition of the Microlite, 
derited from the foregoing examination, coupled with that in 
1837, is this, that it is a columbate of yttria and lime, with a lit- 
tle moisture, adventitious traces of iron, tin, a acid, and 
Uranium. 
I do not possess scioughi of the risinarta to enable me to under- 
take its analysis: but it is a question which I regard with inter 
ést, and shall welcome its final settlement from whatever quarter 
it comes ; though I must be’ excused, in the face of such evidence 
as huvounoeily: cited, <0, frocs-nduicecing At: the mere declaration 
of any authority however ee ‘that its I g C, 
in place of columbie, acid. EI, cI eg Si se ia : i 
by sige; is not the motive geoptacraea peruntelote Tam free 
to say, that I have long p ¢ several ng a ies which 
point towards an identity bet a Yellow yttro- 
tantalite of Ytterby, although “a closeexamination’” of several 
points in the history of the latter substance; yet requires to’ be 
made, in order to establish: the truth of such a a ie ss 
“New Hayen, May 15, 1842. 
~The remarks of Prof. Shepard having been communicated to Mr. A. A. Hayes, 
he candidly admits their correctness.—Eps. 
“Vain No.1 Apatow, 192 : 16 
