Royal Society. 145 



oxide of uranium, although contaminated with a little zirconia, 

 remained in solution. It was only by the repetition of this pro- 

 cess that a separation could be effected. 



From the solution of the precipitated oxides and sulphides in 

 nitro muriatic acid, after neutralization with ammonia, oxalate 

 of ammonia precipitated yttria and the oxides of cerium, whilst 

 peroxide of iron and protoxide of manganese remained in solu- 

 tion. The precipitate produced by oxalic acid was dissolved in 

 sulphuric acid, the excess of the latter driven off, and the 

 residue dissolved in water. This solution, when concentrated, 

 exhibited the property of depositing a crystalline salt when 

 heated, which again dissolved on cooling — a property by which, 

 as is well known, thorina is distinguished. But its separation 

 from the oxides of cerium, as also from small quantities of zir- 

 conia, was very difficult, and could only be approximately effected, 

 partly by adding to the solution of the oxalates so much hydro- 

 chloric acid that only the oxalates of protoxide of cerium and 

 yttria dissolved, and oxalate of thorina (which, of all the oxides 

 precipitated by oxalic acid, is most difficult of solution in hydro- 

 chloric acid) remained undissolved, and partly by treating the 

 oxalates with a solution of acetate of ammonia, to which a little 

 free acetic acid had been added, in which oxalate of thorina dis- 

 solves readily, but the other oxalates with difficulty. 



In order to obtain a certain result, I had the analysis repeated 

 once more by Mr. Stephens. The found quantities of thorina 

 and zirconia agreed in the two analyses more closely than could 

 have been expected, as the two substances could only be sepa- 

 rated by imperfect methods. Finkener obtained 4*35 per cent., 

 and Stephens 4*25 per cent, of zirconia ; the former 6*05 per 

 cent., the latter 5*55 per cent, of thorina. 



To the rare bodies which had already been found in Samars- 

 kite, we have, therefore, according to these analyses, to add 

 zirconia and thorina. Except in Berzelius's thorite, the latter 

 has hitherto been found only in monazite by Kersten, and in 

 pyrochlore by Wohler ; the latter mineral also contains niobium. 

 It is, however, to be expected that thorina will be found in 

 other tantaliferous and niobiferous minerals. 



XIX. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



[Continued from p, 73.] 



May 1, fC C\^ the Termination of Nerves in Muscles, as observed 



1862. ^ in the Frog; and on the disposition of the Nerves 



in the Frog's Heart."-— The Croonian Lecture. By Prof. A. Kolliker, 



trt."— The * 

 For. Memb. R.S 



Phil Mag, S. 4. Vol. 25. No. 166. Feb, 1863. L 



