ATOMIC WEIGHTS 121 



Second Series. 



43.8C4 

 43.869 

 43.876 



Mean, 43.8697, ± .0023 



Third Series. 



43.884 

 43.878 

 43.885 



Mean, 43.8823, ± .0015 



Combining all four series we have- 



Marignac 43.874, ± .0044 



Stas, first series 43.8755, ± .0005 



Stas, second series 43.8697, ± .0023 



Stas, third series 43.8823, ± .0015 



General mean 43.8759, ± .00046 



POTASSIUM AND SODIUM NITRATE RATIOS. 



Eatios connecting the alkaline nitrates, chlorates and chlorides have 

 been determined by Penny, Stas and Hibbs. 



The general method of working upon these ratios is due to Penny.' 

 Applied to the ratio between the chloride and nitrate of potassium, it is 

 as follows: A weighed quantity of the chloride is introduced into a flask 

 which is placed upon its side and connected with a receiver. An excess 

 of pure nitric acid is added, and the transformation is gradually brought 

 about by the aid of heat. Then, upon evaporating to dryness over a sand 

 bath, the nitrate is brought into weighable form. The liquid in the 

 receiver is also evaporated, and the trace of solid matter which had 

 been mechanically carried over is recovered and also taken into account. 

 In another series of experiments the nitrate was taken, and by pure hy- 

 drochloric acid converted into chloride, the process being the same. In 

 the following columns of figures I have reduced both series to one stand- 

 ard, namely, so as to express the number of parts of nitrate corresponding 

 to 100 of chloride: 



1 Phil. Trans., 1839. 



