ZTRCONJA. 335 



bonate, sulphate and hydrate of yttria, leave Atom of 

 little doubt that the true atomic weight of this yt 

 earth is 5-25. 



Analogy is in favour of the notion, that yttria Of yttrium. 

 is a compound of one atom of yttrium and one 

 atom of oxygen ; on that supposition, the atomic 

 weight of yttrium will be 4 '25. 



SECT. IV. 



OF THE ATOMIC WEIGHT OF ZIRCONIA. 



WE have no good data for calculating the atomic 

 weight of zirconia. The best at present in our 

 possession, are derived from the composition of 

 the zircan and hyacinth, which have been repeat- 

 edly analyzed by Klaproth and Vauquelin. 

 The constituents of this mineral, as deduced 

 from their analyses, are as follows : 



Zirconia 69-0 65 64-5 70 64-5 66 Analyses of 



Silica 26-5 33 32'5 25 32 31 



Oxide of iron 0-5 1 1-5 0-5 2 2 



96-0* 99 1 98-5 J 95-5 98-5 1| 



The great difference in these results renders it 

 probable that none of the analyses is quite cor- 



* Klaproth Bectrage, I. 222. f Ibid. III. 271. From Norway. 

 \ Ibid. V. 130. From the Circars. Ibid. I. 231. From Ceylon. 

 (I Vauquelin, Jour, de Min. No. XXVI. 106. f Vauquelin, Ibid. 



