192 THE ATOMIC WEIGHTS. 



to : the chloride, after rectification over mercury and potassium, was 

 acted upon by dry ammonia, whereupon the compound TiCl 4 .4NH 3 was 

 deposited as a white powder. This was ignited in dry ammonia gas, and 

 the residue, by means of chlorine, was reconverted into titanic chloride, 

 which was again repeatedly rectified over mercury, potassium, and po- 

 tassium amalgam. The product boiled steadily at 135. This chloride, 

 after weighing in a glass bulb, was decomposed by water, the titanic acid 

 was precipitated by ammonia, and the chlorine was estimated in the 

 filtrate as silver chloride. Three analyses were performed, yielding the 

 following results. I give the actual weighings : 



1.470 grm. TiCl 4 gave 4.241 grm. AgCl and .565 grm. TiO 2 

 2.330 " 6.752 .801 " 



2.880 " 8.330 " 1.088 " 



The ".801 " in the last column is certainly a misprint for .901. Assum- 

 ing this correction, the results may be given in three ratios, thus : 



Per cent. TiOifrom TiClv TiCl: looAgCl. TiO 2 : woAgCL 



38.435 34-662 13-322 



38669 34. 508 13.344 



37.778 34-574 13.061 



Mean, 38.294, .180 34-58i, .030 13.242, zfc .061 



These three ratios give three widely divergent values for the atomic 

 weight of titanium, ranging from about 36 to more than 56, the latter 

 figure being derived from the ratio between AgCl and TiCl 4 . This value, 

 56, is assumed by Demoly to be the best, the others being practically 

 ignored. 



Upon comparing Demoly's figures with those obtained by Rose, certain 

 points of similarity are plainly to be noted. Both sets of results were 

 reached by essentially the same method, and in both the discordance 

 between the percentages of titanic acid and of silver chloride is glaring. 

 This discordance can rationally be accounted for by assuming that the 

 titanic chloride was in neither case absolutely what it purported to be ; 

 that, in brief, it must have contained impurities, such for example as 

 hydrochloric acid, as shown in the experiments of Pierre, or possibly 

 traces of oxy chlorides. Considerations of this kind also throw doubt 

 upon the results attained by Pierre, for he neglected the direct estimation 

 of the titanic acid altogether, thus leaving us without means for correctly 

 judging as to the character of his material. 



In 1883* Thorpe published a series of experiments upon titanium 

 tetrachloride, determining three distinct ratios and getting sharply con- 

 cordant results. The first ratio, which was essentially like Pierre's, by 



* Berichte Deutsch. Chem. Gesell., 16, 3014. 1883. 



