THALLIUM. 187 



the series, were both converted into chloride. In the latter the chlorine 

 was estimated as silver chloride, which was weighed on a Gooch filter, 

 with the results given below, which are sensibly identical. The TlCl 

 equivalent to 100 parts of AgCl is stated in the last column. 



TlCl. AgCl. Ratio. 



Crystals 3-9146 '2.3393 i67-34i 



Mother liquor 3-34t5 1.9968 , 167-343 



Mean, 167.342 



The general mean of Lamy's and Hebberling's determinations of this 

 ratio gave 166.555, dr .0865. If we arbitrarily assign Wells and Pen- 

 field's mean equal weight with that, we get a new general mean of 

 166.948, ± .0610. 



The ratios to be considered are now as follows : 



(I.) BaSO^ : TI^SO^ : : 100 : 216.754, zh .1387 



(2.) AgCl : TlCl : : 100 : 166.948, zb .0610 



(3.) Agl : Til : : lOO : 140.648, =b .016 



(4.) Tl : TINO3 : : lOO : 130.39I, i .00034 



(5.) Tl.SO, : TI2 : : loo : 80.953, ± .0030 



(6.) TI2O3 : TI2 : : lOO : 89.481, ± .0040 



(7.) 2TINO3 : T1.A : : 100 : 85.713 



(8.) TljSO^ : T]203 : : 100 : 90.465, dr .0020 



(9-) TI2O3 : 3H2O : : 100 : 11.837, zb .0029 



And the antecedent data are these : 



= 15.879, zh .0003 N = 13.935, =t .0021 



Ag = 107.108, ± .0031 S = 31.828, rb .0015 



CI ^ 35.179, ± .0048 AgCl = 142.287, d= .0037 



1 = 125.888, zb .0069 Agl = 232.996, zb .0062 



Ratio number seven rests upon a single experiment, and the atomic 

 weight of thallium derived from it must therefore be arbitrarily weighted. 

 It has been assumed, therefore, that its probable error is the same as that 

 from number eight. Taking this much for granted, we have nine values 

 for thallium, as given below : 



From (i) Tl = 203.478, zb .1610 



From {2) " ^ 202.366, zb .0872 



From (3) " ^ 201.816, zb .0389 



From (4) " ;= 202.595, zb .0117 



From (5) " = 202.614, dz .0330 



From (6) " = 202 620, zb .0775 



From (7) " ^ 202.679, ± -0483 



From (8) " ^= 202.496, zb .0483 



From (9) " = 202.746, zb .0576 



General mean Tl ^ 202.555, zb .0098 



If = 16, Tl = 204.098. 



