118 Want of Idejitity between Microlite and Pyrochlore. 



vailing ; and according to the rules of forming the species in 

 mineralogy, Microlite must still stand distinct from Pyrochlore. 



Let us now turn to a review of the analysis of Mr. Hayes. 

 This gentleman has not in any form, alluded to a paper of mine, 

 entitled ^^ Chemical Examination of Microlite,'''' and published 

 in Vol. XXXII, p. 338, of this Journal. To save the reader the 

 trouble of referring to that article, I will simply quote from it so 

 far as to say, that I found the Microlite to be a columbate of 

 lime and yttria, with moisture and traces of uranium and tung- 

 stic acid, l^he details of the examination were fully given in 

 that communication ; and in particular, the proofs that the mine- 

 ral was a columbate. My surprise was therefore not inconsidera- 

 ble, to find the subject of my former labors held up in a light so 

 novel, as that of being a salt of a totally new and non-isomorphic 

 genus. 



The paper of Mr. Hayes in support of his views, is out of pro- 

 portion full on points, where the evidence is unsatisfactory ; and 

 silent, where the reader might appreciate its value as aifecting the 

 point at issue : for I hold the blowpipe characters of complex 

 bodies like the Microlite to be simply sufficient for furnishing the 

 chemist to tolerable guesses, in aid of subsequent and more cer- 

 tain experiments with chemical reagents, upon the decomposed 

 and separated ingredients of the mineral. After nearly a page of 

 blowpipe results, many, if not all, of which would be likely, in 

 other hands (with different lamps, blowpipes, and lungs, as well 

 as different sized specimens and proportions of fluxes), to be af- 

 forded from specimens of half a dozen other species as well as 

 from Microlite, we have the steps of the analysis given in the 

 following words. " One grain of the mineral which had been 

 dried was decomposed ; the titanic acid carefully separated and 

 dried, it weighed 80 ; this had the chemical characters of pure 

 titanic acid. 



" The solution of the oxides from the titanic acid gave a pre- 

 cipitate of sulphate of tin, v^hen treated with sulphohydric acid, 

 and the sulphate* oxidized before the blowpipe gave with soda a 

 globule of tin. Sulphohydrate of ammonia gave a black pre- 

 cipitate, which when roasted contained oxides of iron and ura- 

 nium, with traces of oxide of cerium. The fluid remaining gave 



* The sulphuret of tin is here referred to, by Mr. Hayes, in this as well as in 

 the previous line. 



