138 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



The curve for 1909 shows fluctuations which disturb the 

 rhythm, and when that of 1910 was examined it differed so 

 markedly from 1907 and 1908 that it appears proper to repro- 

 duce it here (Fig. 4). The fluctuations have a range of about 

 0-28° C. above and below the mean, and they are irregular 

 so that they fit in badly with the tidal curve of the same year : 

 thus, opposite the tidal maximum of February 12th the tem- 

 perature fluctuation nearly disappears . Weather conditions have 

 been discussed above, particularly in connection with the rapid 

 and unusual rise of temperature during March, 1907, at More- 

 cambe Bay Ship. The mildness of the early months of 1910, 

 particularly February, are indicated in the smoothness of the 

 ten-day average curve, which contrasts strongly with the 

 steeper curve for the Bahama region. In examining the 

 temperature changes from day to day, however, we are not 

 only dealing with general conditions, but also with the particu- 

 lar conditions for each day. In discussing the smoothed 

 ten-daily curves it was found that in their early months 1907 

 and 1908 were " strong " years. Whatever were the conditions 

 on the Lancashire coast they were such that they not only 

 caused large differences between the temperatures, day by 

 day, at the two lightships, but they actually altered the shapes 

 of the two curves. It is during these years, therefore, that 

 one might expect the general conditions prevailing over the 

 great sand-banks to impress themselves on the temperature of 

 the water offshore from the Bay and make minor differences. 

 In 1910, however, the inshore conditions may not have been 

 so marked as to do this so far out as the lightships. It is quite 

 impossible, of course, to give due weight to all the factors 

 concerned, but some that undoubtedly operate can be men- 

 tioned, just to show the conditions that may hide the tidal 

 effects. The direction of the wind, for instance, will have 

 much influence. The winds themselves warm or chill the banks. 

 They may cut the tide or hold it back. They may raise the tide 



