ATOMIC WEIGHTS 



123 



Mean, 135.627, 

 Now, combining, we have: 



Penny, 1st series 135.636, ± .0011 



Penny, 2d series 135.633, ± .0011 



Stas 135.6423, ± .0014 



Hibbs 135.627, ± .0026 



General mean 135.636, ± .0007 



.0026 



By the same general process Penny ^ determined how much potassium 

 nitrate could be formed from 100 parts of chlorate. He found as follows : 



82.505 

 82.497 

 82.498 

 82.500 



Mean, 82.500, ± .0012 



For 100 parts of sodium chlorate he found of nitrate: 



79.875 

 79.882 

 79.890 



Mean, 79.8823, ± .0029 



For the ratio between the chloride and nitrate of sodium Penny made 

 two sets of estimations, as in the case of potassium salts. The subjoined 

 fig-ures give the amount of nitrate equivalent to 100 parts of chloride : 



First Series.- 



-NaCl treated with HNOs 

 145.415 

 145.408 

 145.420 

 145.424 

 145.410 

 145.418 

 145.420 



Mean, 145.4164, ± .0015 



1 Phil. Trans., 1839. 



