132 



TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



While the position of Bahama Bank Vessel does not exclude 

 this effect of the bank water (as shown by a comparison of the 

 temperatures and salinities with those from Stations V-VII, 

 where the conditions are such as to let the Atlantic water become 

 a factor), the effect is much less evident than it is at Morecambe 

 Bay Light Vessel. The cause of the variations from the simple 

 harmonic curve in the graphs of sea-temperature at both 

 Bahama Bank and Morecambe Bay ships may be looked for, 

 therefore, in the local inshore conditions. 



One clue to the causes of these variations may be found 

 in the various positions of the minima of sea-temperature. 

 Thus, the differences between the dates of the minima of the 

 smoothed curves for Bahama and Morecambe Bay Ships are 

 shown below : — 





Morecambe 

 Bay. 



Bahama 

 Bank. 



Difference. 



1907 



January 31 

 February 14 

 March 1 

 January 30 

 February 9 

 February 9 

 January 26 



February 20 

 March 8 

 March 6 

 February 3 

 February 11 

 February 4 

 January 22 



Days. 

 20 



1908 



23 



1909 



5 



1910 



4 



1911 



2 



1912 



5 



1914 



4 







Thus, the difference in the dates at which the minima occur 

 may be from 2 to 23 days. The years 1912 and 1914 are the 

 only ones in which the minimum for Bahama Bank occurs before 

 that for Morecambe Bay. There was a marked deficiency in 

 both the air-temperature and the amount of sunshine until 

 February 10th in 1912 and until January 24th in 1914 ; and 

 apparently the temperature of the banks in Morecambe Bay, 

 which are laid bare by the tides, cooled the offshore water and 

 delayed the usual rise of sea- temperature in those years. 

 1907 and 1908 are, however, very exceptional years, for the 

 difference in the dates of occurrence of the minima were 20 

 and 23 days respectively ; and they are also years which 



