Watit of Identity between Microlite and Pyrochlore. 121 



A portion of the acid was fused with carbonate of potash in a 

 platina crucible ; water was boiled upon the mass, whereby a 

 complete solution was effected. To a portion of the solution, hy- 

 drochloric acid was added. It first occasioned a cloudiness, but 

 subsequently the fluid became clear. The same effect was produ- 

 ced by oxalic add. Ferrocyanide of potassium afforded with the 

 oxalic solution, a yellow precipitate, and the tincture of nut-galls 

 with the same, a rich orange precipitate. 



A portion of the acid was fused with biphosphate of soda on 

 a platina hook, in the inner flame of the blowpipe : a transparent 

 glass was obtained, which was colorless while hot, as loell as after 

 cooling. Fused with soda before the blowpipe, an opake, white 

 bead was obtained. 



My conclusion concerning the composition of the Microlite, 

 derived from the foregoing examination, coupled with that in 

 1837, is this, that it is a colurabate of yttria and lime, with a lit- 

 tle moisture, adventitious traces of iron, tin, tungstic acid, and 

 uranium. 



I do not possess enough of the mineral to enable me to under- 

 take its analysis : but it is a question which I regard with inter- 

 est, and shall welcome its final settlement from whatever quarter 

 it comes ; though I must be excused, in the face of such evidence 

 as I have already cited, from acquiescing in the mere declaration 

 of any authority however high, that its prime ingredient is titanic, 

 in place of columbic, acid. 



To show that a zeal to defend a species because it was put forth 

 by myself, is not the motive for the present reclamation, I am free 

 to say, that I have long perceived several striking analogies which 

 point towards an identity between Microlite and the Yellow yttro- 

 tantalite of Ytterby, although " a close examination" of several 

 points in the history of the latter substance, yet requires to be 

 made, in order to establish the truth of such a conjecture. 



New Haven, May 15, 1842. 



The remarks of Prof. Shepard having been communicated to Mr. A. A. Hayes, 

 he candidly admits their correctness. — Eds. 



Vol. xmi, No. 1.— April-June, 1842. 16 



