136 ATOMIC WEIGHT DETERMINATIONS. 



driving off the acid by heating the salt in a porcelain cruci- 

 ble. Platinum is attacked. The number is the mean of 

 four experiments ; extreme difference, 0.698. The zinc 

 was prepared by mixing pure oxide with carbon, and distill- 

 ing in a current of hydrogen. {Berzelius' Jahresbericht, ^^, 

 1844, 132 ; (Efversigt af Kongl Vet. A/cad. HandL, 1, 3.) 



ZIRCONIUM. 



Deville and Troost have determined the vapor density of 

 the chloride. It agrees with an atomic weight of about 90. 

 (L. Meyer, I c.) 



J. J. Berzelius : 89.6 (O = 16). 



In one experiment the sulphate was decomposed with 

 ammonic hydrate, the oxide weighed and the sulphuric 

 acid precipitated with barium chloride. In five experi- 

 ments the sulphate was decomposed at a white heat, ammo- 

 nium carbonate being added at the close of the operation. 

 The mean result was that 100 parts of sulphuric anhydride 

 unite with 75.853 parts of zirconium oxide ; extreme differ- 

 ence, 0.23. Berzelius deduces the value 840.08 for = 

 100, S = 201.165 ; on the supposition that the oxide con- 

 tains three atoms of oxygen. [Being a binoxide, this re- 

 lation gives Zr = 89.6 for O = 16.] The sulphate seems to 

 have been prepared by dissolving the oxide in sulphuric 

 acid and expelling the excess of acid by heat. [Poggend. 

 Ann., 4, 1825, 126.) 



R. Hermann : 



This chemist made some experiments on the chloride 

 getting in three determinations a mean of 839.45 for := 

 100 and on the tri-oxide supposition. The extreme differ- 

 ence was 20.1. 01 = 443.65. The chloride was produced 

 by heating the oxide with carbon in a current of chlorine. 

 Hermann adopts not his own but Berzelius' determination. 

 {Erdmami's Journ. filr Prak. Chem., 31, 1844, 77.) 



C. Marignac : 90 (O = 16). 



Determined from analyses of potassium fluo-zirconiate. 

 The salt was decomposed with sulphuric acid, the excess 



