150 THE FITNESS OF THE ENVIRONMENT 



shall always be equilibrium between the car- 

 bonic acid in the solution and in the atmos- 

 phere. Further, let the temperature be such 

 that the absorption coefficient of carbon 

 dioxide shall be 1.000. Then the successive 

 states of the solution will be approximately 

 as recorded in the following table: — 



From the beginning of the experiment until 

 almost 250 grams of hydrochloric acid have 

 been added", neither alkalinity nor acidity is 

 double in intensity the values which obtain 

 in a perfectly neutral solution. This amounts 

 to a constancy of reaction which, until a few 

 years ago, was scarcely known to the chemist 

 at all. Such close approach to neutrality 



