ATOMIC WEIGHTS 73 



careful calcination, with all the precautions taken to avoid loss. His 

 figures are subjoined : 



KBrOi. KBr. Per cent. 0. 



6.801 4.849 28.7016 



3.480 2.483 28.6494 



6.320 4.506 28.7025 



23.186 16.521 28.7458 



Mean, 28.6998, ± .0133 

 Hence KBr = 119.349, ±.0596. 



Marignac attempted to analyze silver bromate, but found difficulties in 

 drying the salt. He also made some experiments upon the precipitation 

 of silver bromate by potassium chloride, but published no details of his 

 determinations. He merely states that from 31.32 to 31.47 parts of KCl 

 were needed to precipitate the silver from 100 parts of bromate. 



Stas ' effected the analysis of silver bromate by reduction with sul- 

 phurous acid, its content in water having been previously determined. 

 After applying all corrections the subjoined percentages of oxygen were 

 found from the weight of the bromate and that of the residual silver 

 bromide : 



• 20.351 

 20.347 



Mean, 20.349, ± .0014 



Hence AgBr= 187.884, ±.0133. 



The percentage of oxygen in potassium iodate has been determined by 

 Millon.' In three experiments he found : 



22.46 

 22.49 



22.47 



Mean, 22.473, ± .005 



Hence KI = 165. 590, ±.0384. 



According to Marignac'' potassium iodate loses iodine when calcined, 

 and is therefore unsuited to atomic weight determinations. 



Millon also estimated the oxygen in silver iodate, getting the following 

 percentages : 



17.05 

 17.03 

 17.06 



Mean, 17.047, ± .005 



^ Oeuvres ConiplOtes, 1, 635. 



2 Ann. Chim. Ph.ys. (3), 9, 400. 184.3. 



* Oeuvres Completes, 1, 85. 



