SEA-FISHERIES LABORATORY. 289 



cipal feature is the approximate uniformity of tempera- 

 ture over the entire area. There is a large, irregular 

 patch of water in the middle of the Irish Sea, where the 

 temperature is about 9° : the narrow tongue which is seen 

 to pass to the west of Anglesey terminates a little way 

 to the south, as the observations made by the Irish 

 Fishery vessel " Helga " during this month show. Near 

 the coast of Lancashire are the highest temperatures 

 observed, 10° to about 11°. Everywhere in the area 

 covered by the isotherms the gradients are slight, that 

 between Nelson Buoy and Red Wharf Bay being about 

 1'5°, while between the former point and the Bahama 

 Bank, the gradient is less still. Along the line of 

 Stations between Piel Gas Buoy and Bahama Bank the 

 isotherms run rather irregularly, a condition which is 

 to be traced to the rapid tidal streams which oscillate in 

 this direction between Morecambe Bay and the sea off- 

 shore, and also to the fact that the sea-temperature is 

 rising rapidly at this time of year : the daily increment 

 at Carnarvon Bay Light Vessel is about + 0'08. At 

 this time of year the highest temperature gradients are 

 those at right angles to the coast line of Lancashire, the 

 isotherms running nearly parallel to this, and being 

 closest to one another here. 



Chart II represents the distribution of temperature 

 during November, the other "mean" month. There 

 are notable differences, however, in the course of the 

 isotherms at this time of year. The sea-temperature is 

 rising rapidly in May, but falling less rapidly in 

 November, the daily increment during this month at 

 Carnarvon Light Vessel being— 0'038 in degrees Centi- 

 grade. The water off-shore is warmer than that in-shore 

 in November, but colder in May. There is a tendency 

 for the isothermal lines to bend in towards the coast of 



