1870.] 



of Zirconia and the Oxides of Uranium, 



199 



number of moderately broad absorption-bands in the blue end (Nos. 1, 2, 

 and 3); and the same is also seen in the case of several natural minerals; 

 whereas the jargon gave a most unusually large number of narrow black 

 lines (fourteen quite distinct, besides others more faint, and a single broader 

 band which I cannot separate into lines), extending from the red end, so 

 that nearly all occur in that part of the spectrum which is entirely free 

 from bands in all previously known compounds of uranic oxide. This 

 same general fact was also seen in the spectrum (No. 6) of the opaque blow- 

 pipe-beads gently flamed, as described in my former paper. These differ- 

 ences will be better understood by means of the following drawing, which 

 shows three of the most striking spectra of uranic salts, that of uranate of 

 soda, and the two which are rendered so abnormal by the presence of zirconia. 



Ked End. Blue End. 



Spectra of Uranic Compounds. 



Nos. 1, 2, and 3. Uranic salts of the common type, viz.: — 



1. Native phosphate. 



2. Nitrate in crystals. 



3. Acetate in crystals. 



No. 4. Uranate of soda in the carbonate-of-soda bead. 

 Nos. 5 and 6. Uranic compounds with zirconia, viz. : — 



5. Jargon after ignition. 



6. Crystalline borax blowpipe-bead. 



I will not now enter into a description of the various chemical and 

 physical facts which seemed to warrant the conclusion that zircons some- 

 times contain a new earth ; but taking these into consideration, there seemed 



VOL. XVIII. Q 



