so 



Dr. G. H. Bailey. 



[May 9, 



ceeds rapidly with a copious evolution of sulphur dioxide, and even 

 with the production of free sulphur. 



Dilute sulphuric acid (1:1) acts more slowly with the evolution of 

 hydrogen. 



Zirconium is acted upon also by chlorine and bromine, in which, 

 on gentle heating, it undergoes vivid combustion, forming the tetra- 

 haloid derivatives, and this is, indeed, a convenient method for ob- 

 taining these bodies. The iodide could not be obtained. When the 

 zirconium was filtered, after the digestion with dilute hydrochloric 

 acid, and dried, it was found to have occluded hydrogen. This was 

 removed by exposing it in vacuo for some days, and removing the 

 hydrogen by the mercury pump. 



The Oxides. — The only points for remark in addition to what has 

 already been published, relate to the reduction (?) of zirconia and to 

 the peroxide of zirconium. 



With regard to the former it has already been noticed that when 

 zirconia is heated, surrounded by the reducing flame of coal-gas, it 

 blackens. This blackening is only superficial, however, and is in all 

 probability due to a thin deposit of carbon, and it reoxidises readily 

 to a white powder when heated in air, with a decrease of weight — 

 small, indeed, but distinct. Heated at the highest temperature of 

 the blowpipe flame in hydrogen, it undergoes no reduction. 



Zirconium Peroxide, Zr0 3 . 



Cleve (' Paris Soc. Chim. Bull.,' vol. 43, p. 53) precipitated an 

 oxide, to which he assigned the composition Zr0 3 , by adding ammonia 

 and hydrogen peroxide to a solution containing a zirconium salt ; my 

 own experiments (' Chem. Soc. Journ.,' vol. 49, p. 481), in which the 

 oxide was precipitated from a dilute solution by the addition of 

 hydrogen peroxide alone, the solution being slightly acid, gave an 

 oxide agreeing well with the composition Zr 2 5 ; it was found also 

 that an oxide resembling Cleve's could be obtained without the 

 addition of ammonia. In order to see whether the peroxide, Zr0 3 , 

 was identical with that obtained by Cleve, I precipitated a large 

 quantity of a moderately concentrated solution of zirconium sulphate, 

 containing a slight excess of acid — 



(a.) By the addition of hydrogen peroxide alone. 

 (b.) By the addition of hydrogen peroxide, and then ammonia 

 until just alkaline. 



Mean 

 determinations. 



( a- ^ Calculated for 



(a.) (6). Zr0 3 . 



Zr 64-92 64-97 65*21 



O 35-08 35-03 34'79 



