Summary. 



1. A consideration of the C'Oo -producing and CO^- 

 absorbing factors of the earth shows that we have no reason 

 to thinli that equilibrium will, as a rule, exist between them. 

 The percentage of carbonic acid in the atmosphere must there- 

 fore be variable (pp. 416—19). 



2. At the same tension (0.03 ^"/0) the ocean contains free 

 and loose carbonic acid to the amount of about 27 times that 

 of the atmosphere. It must give off about Vio of this if the 

 tension should sink to 0.02 °/o, and absorb V/is if it should 

 rise to 0.04 °/o. The ocean is therefore capable of acting as a 

 regulator on the variations of the carbonic acid in the atmo- 

 sphere, provided the processes of absorption or liberation be 

 sufficiently rapid (pp. 420 — 21). 



3. These processes must be considered as extremely rapid 

 since a tension-difference between the ocean and the atmo- 

 sphere of only 0.001 "/o will cause the yearly absorption (or 

 elimination) of upwards of 4000 million tons of carbonic acid, 

 corresponding to IV2 times the yearly output of coal by man 

 (pp. 422—23). 



4. Bi/ a comparison between the average CO „-tension of 

 the ocean-surface and the percentage of the gas in the atmo- 

 sphere it will be possible to ascertain whether the latter is in- 

 creasing or decreasing or perhaps stationary. The evidence now 

 available points towards the first of these alternatives^ but it is 

 not sufficioit to decide the question (pp. 423 — 25). 



5. The action of the ocean will retard and diminish any 

 alteration in the percentage of carbonic acid in the atmosphere 



XXVI. 28 



