226 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



temperature of the water of the Irish Sea unaffected by 

 the influence of the land. It is very probable that this is 

 the case, and that the water here has much more an 

 " open-sea " character than in any part of the Irish Sea 

 North of the latitude of Anglesey. Conversely, the 

 Morecambe Bay and Liverpool North-west Light Ship 

 sea temperatures may be regarded as affected by the 

 influence of the land : those taken at the Bahama Bank 

 vessel are intermediate between the two series mentioned. 

 The Lancashire observations at stations 3, 4, 5, 6, 7, 11, 

 12, 13, 15, have therefore been corrected by just that 

 difference which is shown on the curve for the Carnarvon 

 Bay series, between the mean dates of Lancashire and 

 Irish cruises. The observations made at the other stations 

 have been similarly corrected from the Morecambe Bay 

 Light Vessel series. 



The temperatures taken at the coastal stations have 

 been reduced to monthly means, and then smooth curves 

 have been drawn. In the case of most of these stations 

 the series is fairly complete, except in one or two months. 

 Values for these dates have been obtained graphically, 

 since interpolation formula?, such as those employed in 

 the evaluation of mathematical functions, cannot easily 

 be applied. The method of graphing a number of such 

 series suggested by D'Arcy Thompson* is of the greatest 

 value, and has been employed in the present investigation. 

 A number of stations, which we have reason to believe are 

 associated together, inasmuch as the variations from one 

 to another are in the same direction, are grouped, and 

 the monthly temperature means are plotted to the same 

 axes of co-ordinates. Fig. 24 represents such a family 

 of curves, that for Bed Wharf Bay being taken as the 

 standard one. The values of the ordinates for each of the 



Ibid. p. 172. 



