TITANIUM. 207 



TITANIUM. 



The earliest determinations of the atomic weight of tita- 

 nium are due to Heinrich Rose.* In his first investigation 

 he studied the conversion of titanium sulphide into titanic 

 acid, and obtained erroneous results ; later, in 1829, he pub- 

 lished his analyses of the chloride.f This compound was 

 purified by repeated rectifications over mercury and over 

 potassium, and w-as weighed in bulbs of thin glass. These 

 were broken under water in tightly stoppered flasks ; the 

 titanic acid was precipitated by ammonia, and the chlorine 

 was estimated as silver chloride. The following results were 

 obtained. In a fourth column I give the TiO. in percent- 

 ages referred to TiCl^ as 100; and in a fifth column the 

 quantity of TiCl^ proportional to 100 parts of AgCl: 



Mean, 42.933, ± .121 33.156,^.019 



If we directly compare the AgCl with the TiO 2 we shall 

 find 100 parts of the former proportional to the following 

 quantities of the latter : 



14-243 

 14.081 



14-153 

 14-373 

 14-324 



Mean, 14.235, dr .036 



From all these figures we can get three values for Ti, thus : 



* Gilbert's Annalen, 1823, 67 and 129. 



f Poggend. Annal., 15, 145. Berz. Lehrbuch, 3, 1210. 



