Biographical Account of Br. Wollaston, by Dit. Thojias Thomson. 141 



mode of experimenting on a minute scale, and of the sagacity which 

 enabled him to draw the proper conclusions from very simple premises. 



4. Dr. Wollaston's discovery regarding titanium, ought not to be passed 

 over in silence. Titanium is the name given by Klaproth to a new metal 

 discovered by Mr. Gregor in the valley of Menachan in Cornwall, and 

 called on that account menachine. Mr. Gregor published an account of 

 his discovery in 1791. In the year 1795 Klaproth discovered a new 

 metal in a mineral at that time distinguished by the name of red schorl, 

 to which he gave the name of titanium. And in 1797 he made a com- 

 parative set of experiments on the menachine of Gregor and his own 

 titanium, by which be established the identity of these two metals with 

 each other. All attempts to reduce the oxide of titanium to the metallic 

 state failed, if we except the small quantity of metallic titanium ex- 

 tracted by Vauquelin and Hecht in 1796, and the subsequent method 

 of reducing the oxide to the metallic state contrived by Liebig in 1831, 

 and deduced by him from Henry Rose's experiments on ammonio-chloride 

 of titanium. 



iled cubes having the metallic lustre, are occasionally discovered in 

 the slag of the hearths of the great iron smelting houses," so abundant in 

 this neighbourhood and in Wales. These cubes were examined by Dr. 

 Wollaston in 1822, and shown to possess the characters of titanium in 

 the metallic state. He found the cubes to consist of metallic titanium 

 of the sp. gravity 5 3, and to be hard enough to scratch rock crystal. 



Such was the state of our knowledge of these cubes of metallic tita- 

 nium, as was supposed, when Wuhler published an elaborate set of experi- 

 ments on them in the year 1850. He showed that they always contained 

 graphite mechanically mixed. By*a very ingenious but complicated set 

 of experiments, Wcihler showed that the metallic cubes of supposed tita- 

 nium were, in fact, composed of titanium, azote, and carbon, in the pro- 

 portions — 



Titanium, 78.00 



Azote, , 1811 



Carbon, 8-89 



The carbon was combined with azote, constituting cyanogen,"while the 

 remainder of the azote was united with the titanium, constituting an 

 azotidc. The crystals, according to these experiments, are composed of — 



Cyanide of titanium, 1621 



Azotide of titanium, 88-79 



or, 100-00 



1 Atom cyanide of titanium. 

 3 Atoms azotide of titanium. 



In the year 1823 when Dr. Wollaston's paper was published, the 

 science of chemistry was not far enough advanced to enable iiim to make 

 a complete and satisfactory analysis of this very remarkable compound. 



