399 



Atlantic that was carried up into the Davis-Strait and diluted 

 with freshwater the figures would indicate that the average 

 dilution amounted to 5.6 per cent of freshwater with an average 

 alkalinity of 14.3 or about the half of that of the seawater. 



In Walther & Schirlitz' paper (quoted above) an examination 

 of brakish water taken near the mouth of the Volturno in the 

 Bay of Gaëta is mentioned. Unfortunately, the salinity is not 

 given, but the very high alkalinity — 68.5 mgrs. — is rightly 

 attributed by the Authors to the river-water coming down from 

 the extensive beds of limestone in the Appennines. 



When we try to consider the alkalinity of the ocean as a 

 whole we find two causes of augmentation, viz. The alkali of 

 the bottom and the alkali of the freshwater, carried to the sea, 

 and one of diminution, the fixation of lime by the marine 

 organisms. 



It is generally stated that the ocean must have attained, 

 during the immense space of time, a stable equilibrium. 

 This may be true with regard to the salinity but we have not 

 sufficient reason to believe that it also holds good for the 

 alkalinity. A large part of the carbonates no doubt perform a 

 regular circulation being fixed by the organisms, converted into 

 rocks of limestone and dolomite, dissolved by the meteoric 

 waters and again carried to the sea^) but the several phases 

 of the process are absolutely independent of each other, and 

 the velocity of the motion as a whole may, for all we know, 

 be very variable. 



Alongside the circulation runs a constant production of 

 carbonates from alkaline silicates and even should this process 



^) The yearly amount of lime carried to the sea by the rivers of the earth 

 is variously estimated: t.3 x 10* tons [Challenger narrative vol. 1 p. 980) 

 3.1 X 10^ tons (Journ. of Geol. vol 7 p. 569). The figures are probably 

 not very reliable, but they may indicate that the real quantity is some- 

 thing of this order of magnitude. 



