478 Intelligence and Miscellaneous Articles. 



scratches glass and is scratched by quartz and rutile. Its specific 

 gravity is 3*857, that of the rutile being 4*209 ; it is infusible by the 

 blowpipe ; when strongly heated with the phosphorus salt on a cupel, 

 it dissolves completely, and gives in the reducing flame a bluish-violet 

 glass, perfectly similar to that obtained by rutile ; this colour disap- 

 pears in the oxidating flame, but it returns if a globule of tin be added 

 to the fused mass. 



When reduced to powder, anatase is not acted upon either by nitric 

 or hydrochloric acid ; boiling sulphuric acid partially dissolves it ; of 

 one part so treated 0*1918 were dissolved. The insoluble portion 

 was not altered in colour, and gave the same reaction with the salt 

 of phosphorus as it did before treatment with the acid ; the dissolved 

 portion gave by evaporating the acid a white gummy mass, which 

 decrepitated strongly when attempts were made to heat it to redness. 

 It consisted of sulphate of titanium, and gave with the salt of phos- 

 phorus the same reaction as the matter unacted upon. 



A comparative examination having been made in the same way 

 on the rutile of Saint- Yrieix, results almost identical were obtained ; 

 rather less was dissolved by sulphuric acid. 



In order to analyse anatase it was reduced to very fine powder, 

 and fused with eight times its weight of recently prepared bisulphate 

 of soda ; it was quickly and perfectly dissolved. The fused mass 

 was dissolved, when cold, in a large quantity of hot water, and a 

 current of sulphuretted hydrogen was passed into the acid solution ; 

 after some time a small quantity of brown flocculi was deposited, 

 consisting principally of sulphur; these were volatilized by heat, 

 leaving a slight residue, which Was found to be oxide of tin. 



The solution was afterwards heated in order to expel the excess 

 of sulphuretted hydrogen, and then filtered ; a small portion of hy- 

 drochloric acid was added to it, and then sulphite of ammonia suf- 

 ficient to saturate the excess of acid ; sulphurous acid was expelled, 

 and the liquor, when heated, deposited a white flocky precipitate in 

 considerable quantity ; this collected on a filter was readily washed. 

 After calcination it was white with a tint of yellow, and had a shi- 

 ning greasy lustre. By fusing with the salt of phosphorus it evinced 

 the properties of titanic acid. 



The liquor from which this precipitate was separated, was satu- 

 rated with ammonia, and hydrosulphate of ammonia was afterwards 

 added to it ; sulphuret of iron containing a little titanic acid was se- 

 parated; the sulphuret was collected and dissolved in nitric acid, 

 and the solution of iron, separated from the titanic acid which the 

 sulphuret of iron contained, was supersaturated with ammonia, and 

 the peroxide of iron precipitated was collected and weighed. 



The liquor separated from the sulphuret of iron was not rendered 

 turbid, either by oxalate of ammonia or phosphate of soda. 



One hundred parts of anatase yielded 



Titanic acid 98*36 



Peroxide of iron . . I'll 



Oxide of tin 0*20 



99*67 



