CHROMIUM. 247 



The next series, obviously, gives the ratio I 3 : Ag 2 CrO 4 .4NH 3 . 



/ Set Free. Percentage * 



.54356 .51784 95-267 



.54856 .5 20 46 94.877 



.54926 .52322 95.258 



.54906 .52376 95.392 



.54466 .5*910 95.307 



.54536 .51891 95- 15 



Mean, 95.208, =b .0497 



In dealing with the two dichromates Meineke used the acid potassium 

 iodate in place of potassium iodide, the chromate and the iodate reacting 

 in the molecular ratio of 2:1. The thiosulphate was standardized by 

 means of the acid iodate, so that we have direct ratios between the latter 

 and the two chromates. The data are as follows, with the amount of 

 iodate proportional to one hundred parts of the dichromate in the third 

 column : 



Percentage. 



* These figures are not wholly in accord with the percentages of oxygen computed by Meineke. 

 I suspect that there is a misprint among his data as published, probably in the second experi- 

 ment, but I cannot trace it with certainty. 



