ATOMIC AVEIGHTS 341 



then collected upon a filter^ dried, ignited and weighed. The results 

 were as follows : 



4.6680 grm. AgXrO^ gave 4.027 grm. AgCl and 1.0754 grm. CrA- 

 .3.4568 " 2.983 " .7960 



2.5060 " 2.1605 " .5770 



2.1530 " 1.8555 " .4945 



4.3335 grm. AgoCr.Ojgave 2.8692 " 1.5300 



From these weighings three values are calculable for the atomic weight 

 of chromium. The three ratios upon which these values depend we will 

 consider separately, taking first that between the chromic oxide and the 

 original silver salt. In the four analyses of the normal chromate the 

 percentages of CroOg deducible from Berlin's weighings are as follows: 



23.037 

 23.027 

 23.025 

 22.968 



Mean, 23.014, ± .011 



Hence Cr = 52.46. 



And from the single experiment with Ag2Cr207 the percentage of CroOg 

 was 35.306. Hence Cr= 53.34. 



For the ratio between Ag2Cr04 and AgCl, putting the latter at 100, 

 we have for the former : 



115.917 

 115.883 

 115.992 

 116.033 



Mean, 115.956, ± .023 



Hence Cr = 52.67. 



In the single experiment with dichromate lOOAgCl is formed from 

 151.035Ag2Cr2O,. Hence Cri= 52.61. 



Finally, for the ratio between AgCl and CrjOa, the five experiments of 

 Berlin give, for 100 parts of the former, the following quantities of the 

 latter : 



26.705 

 26.685 

 26.707 

 26.650 

 26.662 



Mean, 26.682, ± .0076 

 Hence Cr = 52.49. 



