On Mean Sea Level and its Flnetuations. 



25 



chan.ife in the distribution of salinity on the suiface of the Atlantic, 

 due to a greater extension northwartl and eastward of the warm 

 cm-rents in autumn as compared witii spring. But our actual know- 

 ledge of the variations of the ocean currents is even now extremely 

 scanty ; and, in trying to correlate them with the variations in sea 

 level of which we have been spealcing, we are very apt to argue in a 

 circle, and to use these variations of level as a proof rather than as a 

 consequence of the existence of variations in the great ocean currents. 

 Again, since the foregoing pages were in proof, J have leceived from 

 Professor Otto Pettersson two important papers,* in which this subject 

 is discussed in connection with many other periodic phenomena which 



/897 8 



FEET 



■Z 

 Fig 



-Annual Means of High Water, Low Water, and Mean Sea Level at 

 Dundee (1897-1912). 



may have their effect on the temperature of the sea and the climate 

 of the earth. It is impossible to do more here than to call attention 

 to these papers. 



II. The Variation of Mean Sea Level from Year to Year. 



Let us now, returning to Tables I. and IV. (pp. 37, 39), consider 

 the variation of Mean Sea Level from year to year. It will be seen 

 that both at Aberdeen and Dundee the differences are striking' in 

 amount, and are not destitute of an appearance of regularity. 



Let us consider in the first place the comparatively brief period, 

 of sixteen years, covered by the Dundee observations. It will be 



* (1) On the Occurrence of Lunar Periods in Solar Activity and tlie Climate 

 of the Earth ; and (2) Climatic Variations in Historic and I'reliLstoric Times. 

 Sv. H>jdro(jr.-Biulo(j. Kommissionen^ Skrijter. Hiift \'.. 1914. 



