SILVER, POTASSIUM, ETC. 13 



60.847 per cent, of residue. When the ignition is rapid, we 

 get 60.942. As no detailed experiments are given, these 

 figures can liave no part in our discussion. 



Last of all we have two series determined by Stas.* In 

 the first series we have the results obtained by igniting the 

 chlorate. In the second series the chlorate was reduced by 

 strong hydrochloric acid, after the method followed by 

 Penny : 



First Series. 

 60.8380 

 60.8395 

 60.8440 

 60.S473 

 60.8450 



Mean, 60.84276, =b .0012 



Second Series. 

 60.850 

 60.853 

 60. 844 



Mean, 60.849, ± .0017 



In these experiments every conceivable precaution was 

 taken to avoid error and ensure accuracy. All weighings 

 were reduced to a vacuum standard ; from 70 to 142 

 grammes of chlorate were used in each experiment; and 

 the chlorine carried away with the oxygen in the first series 

 was absorbed by finely divided silver and estimated. It is 

 difficult to see how any error could have crept in. 



Now, to combine these different series of experiments. 



Berzelius, mean result 60.851, =h .0006 



Penny, " 60.8225,^.0014 



Pelouze, " 60.843, ±.0053 



Marignac, " 60.8392, drz .0013 



Gerhardt, 1st " 60.8757, d= .0020 



'• 2d " 60.9487, rb .001 1 



Maumene, " 60.791, ±.0009 



Stas, 1st " 60.8428, rfc .0012 



" 2d '• 60.849, dr .0017 



General mean, from all nine series, representing forty 



experiments 60.846, ±.00038 



* See Aronstein's Translation, p. 249. 



