NITROCiEN. 45 



Second Scries. 

 43.864 

 43.869 

 43-876 



Mean, 43.8697, =fc .0023 



Third Series. 

 43.894 

 43.878 

 43-885 



Mean, 43.8857, =h .0031 



Combining all four series we have : 



Marignac 43.858, ±z .0044 



Stas, 1st series 43-8755, dr .0005 



" 2d " 43.8697, ± .0023 



" 3d " 43.8857,^.0031 



General mean 43.8715, ±i .0004 



There have also been determined by Penny and by Stas 

 a series of ratios connecting the alkaline chlorides and chlo- 

 rates with the corresponding nitrates. One of these, relat- 

 ing to the lithium salts, will lie studied further on with ref- 

 erence to that metal. 



The general method of working upon these ratios is due 

 to Penny.* Applied to the ratio between the chloride and 

 nitrate of [)otassium 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. Tlien, upon evaporating 

 to dryness over a sand bath, the nitrate is brought into 

 weighable form. The liquid in the receiver is also evapo- 

 rated, and the trace of solid matter which had been mechan- 

 ically carried over is recovered and also taken into account. 

 In another series of experiments the nitrate was taken, and 

 by pure hydrochloric acid converted into chloride; the pro- 

 cess being the same. In the following columns of figures I 



*Phil. Trans., 1839. 



