TITANIUM. SI 



These cubes of metallic titanium are not abso- 

 lutely free from iron. They are not sensibly 

 attracted by the magnet ; but Dr. Wollaston 

 found that, when suspended by a fine thread, a 

 magnet drew it about 20 degrees from the per- 

 pendicular. He succeeded in detecting the 

 presence of iron in it, and calculated the amount 

 of that metal at sJuth part of the weight of the 

 titanium.* From an experiment which I shall 

 state below I am disposed to conclude, that the 

 proportions of iron present in these cubes of ti- 

 tanium is still greater than this. 



When metallic titanium is heated in the open 

 air its surface is oxydized, assuming a blue or 

 rather purple colour. The process goes on bet- 

 ter in melted nitre, and if we add some borax to 

 dissolve the oxide as it forms, the oxydation is 

 still farther accelerated. I found also, that when 

 metallic titanium in powder was fused in a pla- 

 tinum crucible with carbonate of soda, it was 

 converted into protoxide. 



1. Titanium appears capable of combining Oxid 

 with two doses of oxygen, and of forming two 

 oxides. The protoxide is blue, and has been 

 found native in slender elongated octahedrons* 

 which have been distinguished by the name of 

 anatase. It has a specific gravity of 3-857, ac- 

 cording to Hauy. The peroxide, when pure, is 



* Phil. Trans. 1823. p. 200. 

 VOL. II. F 



titanium. 



