180 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
then turns to the West again about halfway between the 
coasts of Lancashire and the Isle of Man, and approaches 
the latter near Castletown. Near the land the water is 
much warmer than offshore. During the period of 
Fic. 13. Probable isotherms in the Irish Sea in August, 1908. 
minimum temperature (February) the direction of the 
isotherms is very much the same, but the change of tem- 
perature is then completely reversed—that is, the water 
