1889.] 



Zirconium and its Atomic Weight. 



79 



When dried and heated in air to a point far below redness it glowed 

 and was transformed into zirconia with a small increase in weight. 

 It evidently consisted of zirconia containing only a small percentage 

 of the metal. When rubbed in an agate mortar, however, it showed 

 no white particles, and the variability of its composition, as shown in 

 these and other experiments, lent no support to the assumption that 

 a lower oxide had been formed. In a second set of experiments, 

 magnesium foil was used, and in this case the foil retained its form, 

 although permeated by metallic zirconium exactly as it does in the 

 reduction of carbon compounds. By separating the foil from the 

 finer powder it was possible to obtain zirconium almost free from 

 oxide. Three specimens were prepared : A resembled those already 

 described, a velvety black powder, B had a slight greenish cast, and C 

 a decided olive-green colour with a slight lustrous appearance. 



It was thought, therefore, that A would prove to be the purest 

 zirconium, judging from the experience of previous experimenters. 



Samples were carefully heated in a stream of air, the moisture and 

 carbonic acid (arising from carbon in the magnesium used) directly 

 determined, and the proportion of Zr and Zr0 2 arrived at by calcula- 

 tion, knowing the original weight of substance taken and the weight 

 of Zr0 2 left in the boat. 



A simply glowed and passed into a white powder as the previous 

 specimens had done, B burnt with a white light much more brightly 

 than A had done, and C gave out a dazzling light resembling in its 

 brightness that of burning magnesium ; when thrown into the flame 

 of a Bunsen burner they gave beautiful white scintillations. 

 The results of the analysis gave the following composition : — 



A. B. C. 



Metallic zirconium . 0*0453 0-1516 0*3383 



Zirconia 0*3434 0*3561 0*0267 



Moisture 0*0100 0*0086 0*0350 



Carbon 0*0015 0*0013 nil 



A careful examination showed that no iron or magnesium was pre- 

 sent, and, indeed, after precipitation of the zirconia, the residual 

 impurity from half a gram weighed less than a milligram, and con- 

 sisted entirely of silica, introduced doubtless by the ammonia used 

 in precipitation. Preparation C was, therefore, almost pure zirconium, 

 containing only a slight admixture of oxide ; rubbed up in an agate 

 mortar it showed a brassy lustre. It is stated generally that zir- 

 conium is hardly acted upon at all by mineral acids or aqua regia, 

 but dissolves in hydrofluoric acid. My own observations confirm 

 these statements, with the exception that concentrated sulphuric acid 

 begins to act in the cold even, and on gently warming the action pro- 



