TITANIUM. 



209 



of Pelouze. I subjoin Pierre's weighings, and add, in a 

 third column, the ratio of TiCl^ to 100 parts of silver: 



-0173 



It will be seen that the fir.st three of these results agree 

 well with each other and are much higher than the remain- 

 ing six. The last four experiments were made purposely 

 with tubes which had been previously opened, in order to 

 determine the cause of the discrepancy. According to 

 Pierre, the opening of a tube of titanium chloride admits a 

 trace of atmospheric moisture. This causes a deposit of 

 titanic acid near the mouth of the tube, and liberates hydro- 

 chloric acid. The latter gas being heavy, a part of it falls 

 back into the tube, so that the remaining chloride is richer 

 in chlorine and poorer in titanium than it should be. 

 Hence, upon titration, too low figures for the atomic weight 

 of titanium are obtained. Pierre accordingly rejects all but 

 the first three of the above estimations : 



From all of Pierre's Ti 



" the first three " 



49.889, dr .096 

 50.259, zfc .063 



The memoir of Pierre upon the atomic weight of titanium 

 was soon followed by a paper from Demoly,* who obtained 

 much higher results. Ho also started out from titanic chlo- 

 ride, which was prepared from rutile. The latter substance 

 was found to contain 1.8 per cent, of silica ; whence Demoly 

 inferred that the TiCl^ investigated by Rose and by Pierre 



* Ami. Chem. Pharm., 72, 214. 



14 



1849. Berz. Jahresb., 30, 58. 



