194 THE ATOMIC WEIGHTS. 



agreeing values for the atomic weight of titanium. The cross ratio, 

 4AgCl : Ti0 2 is not directly given by either of Thorpe's series ; but the 

 data furnished by Rose and Demoly combine into a general mean of 

 4AgCl : Ti0 2 : : 100 : 13.980, .0303. 



Some two years later Thorpe published his work more in detail,* and 

 added a set of determinations, like those made upon the chloride, in 

 which titanium tetrabromide was studied. Three ratios were measured, 

 as was the case with the chloride. In the first, the bromide was decom- 

 posed by water and titrated with a silver solution. 



TiBr. Ag. TiBr : rooAg. 



2.854735 3-349 2 7 85.235 



3.120848 3.66*22 85.241 



4-73"i 8 5-5597 85.230 



6.969075 8.17645 85.234 



6.678099 7.83493 85.234 



Mean, 85.235, + .0027 



In the four last experiments of the preceding series, the silver bromide 

 formed was weighed. The third column gives the TiBr 4 proportional to 

 100 parts of AgBr. 



TiBr^. AgBr, Ratio. 



3.120848 6.375391 48.951 



4.731118 9-663901 48.957 



6.969075 14.227716 48.982 



6.678099 I3-639956 48.959 



Mean, 48.962, .0049 



For the third ratio the bromide was decomposed by water ; and after 

 evaporation with ammonia the residual titanic oxide was ignited and 



TiO.,. Percent. TiO 2 . 

 6.969730 1.518722 21.790 



8.836783 1.923609 21.768 



9.096309 . I-9795J3 21.762 



Mean, 21.773, .0062 



Ignoring Mosander's work as unavailable, we have the following ratios 

 to consider : 



(I.) 4Ag : TiCl 4 : : 100 : 44.017, i .0031 

 (2.) 4AgCl : TiCl 4 : : 100 : 33- I2 3, .0019 

 (3.) 4AgCl : TiO 2 : : 100 : 13.980, =h .0303 

 (4.) TiCl 4 : TiO 2 :: 100 : 42.171, .0022 

 (5.) 4 Ag : TiBr, : : 100 : 85.235, .0027 

 (6.) 4AgBr : TiBr 4 : : 100 : 48.962, .0049 

 (7.) TiBr 4 : TiO 2 : : 100 : 21.773, .0062 



* Journ. Chem. Soc., Feb., 1885, p. 108, and March, p. 129. 



