M. Troost on Zirconium. 257 



Hebberling has also made a communication* on thallium. 

 Besides a careful determination of the atomic weight of the 

 metal, in which he obtained numbers not at all materially differ- 

 ing from those obtained by Lamy and by Werther, he examined 

 the action of the most ordinary chemical reagents on the salts of 

 thallium, and has also made careful determinations of the solu- 

 bility of the chloride, the iodide, and the platinochloride. 



Troost has communicated the results of an investigation f on 

 metallic zirconium. He obtained it crystallized by heating, in a 

 crucible of gas-graphite at the fusing-point of iron, one part of 

 double fluoride of potassium and zirconium with one and a half 

 part of aluminium. When the crucible was cold, the surface of 

 the aluminium was found coated with crystalline lamina? pressed 

 against each other like the leaves of a book. On treating the 

 regulus with dilute hydrochloric acid, at first laminae of zirco- 

 nium were separated ; and when all the aluminium was dissolved, 

 an alloy was left of aluminium and zirconium ; which two metals, 

 from the analogy in their properties, appear to dissolve each 

 other in all proportions. 



The above reaction takes place at a lower temperature ; but 

 then the alloy of zirconium and aluminium is almost exclusively 

 obtained. 



The zirconium, obtained as above, contained 1*28 per cent, of 

 aluminium and 0*55 per cent, of silicon. 



Besides the above method, Troost also obtained zirconium in 

 small microscopic crystals by passing vapour of chloride of zirco- 

 nium over aluminium heated to redness in a porcelain tube tra- 

 versed by a current of hydrogen. It was also obtained in small 

 crystalline plates on decomposing, by the battery, fused double 

 fluoride of zirconium and potassium. These crystals decompose 

 water in the cold. 



Graphitoidal zirconium does not appear to exist, or if so, only 

 under special conditions. Amorphous zirconium, with all the 

 properties described by Berzelius, was prepared by passing chlo- 

 ride of zirconium in vapour over sodium heated to redness in a 

 porcelain tube. 



Crystallized zirconium is a very hard lustrous substance, re- 

 sembling antimony in its colour, brilliancy, and brittleness. It 

 is obtained in very thin plates, about half an inch in length and ap- 

 parently forming an oblique prism. Its density is 4*15, differing 

 little from that of zircon. It is certainly less fusible than sili- 

 con, and is so difficult of fusion that no certain opinion can be 

 expressed regarding its fu sing-heat. 



* Liebig's Annalen, April 1865. 

 t Comptes Rendus, July 17, 1865. 



Phil. Mag. S. 4. Vol. 30. No. 203. Oct. 1865. S 



