SILVER, POTASSIUM, ETC. 37 



Closely following Maumene's paper, there is a short note by Faget,* 

 giving certain mean results. According to this chemist, when potassium 

 chlorate is ignited slowly, we get 60.847 per cent, of residue. When the 

 ignition is rapid, we get 60.942. As no detailed experiments are given, 

 these figures can have 110 part in our discussion. 



Last of all we have two series determined by Stas.f In the first series 

 are 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 

 60.8473 

 60.8450 



Mean, 60.84276, dr .OOI2 



Second Series. 

 6o.8t;o 

 60.853 

 60.844 



Mean, 60.849, .0017 



In these experiments every conceivable precaution was taken to avoid 

 error and insure accuracy. All weighings were reduced to^ a vacuum 

 standard ; from 70 to 142 grammes of chlorate were used in each experi- 

 ment; 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 occurred. 



Now, to combine these different series of experiments. 



Berzelius, mean result 60. 85 1 , dr .0006 



Penny, " 60.8225, dr .0014 



Pelouze, " 60.843, .053 



Marignac, " 60.8392, dr .0013 



Gerhardt, 1st " 60.8757, dr .0020 



" 2d V 60.9487, dr .0011 



Maumene, " 60.791, dr .0009 



.Stas, 1st " 60.8428, dr .0012 



" 2d " 60.849, .0017 



General mean from all nine series, 

 representing forty experiments 60.846, db .00038 



This value is exactly that which Stas deduced from both of his own 

 series combined, and gives great emphasis to his wonderfully accurate 



* Ann. d. Chim. et d. Phys. (3), 18, 80. 1846. 

 f See Aronstein's translation, p. 24Q. 



