282 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



bottom are also very small, and are almost always in the 

 same direction. Even if there were a vertical circulation 

 in this region (and there is no evidence whatever that 

 this is the case), the temperature of the surface water 

 would only be affected to a very small extent by this 

 factor. 



The water along this line extending from Calf of 

 Man to Holyhead probably possesses a more " oceanic " 

 character than does any other part of the Irish Sea, 

 North of Anglesea. It will be seen from Table IX that 

 the annual range of temperature here (5 '4° C.) is less than 

 it is at any other point investigated, and approximates 

 closely to the yearly temperature indicated in the Atlantic 

 Ocean to the West of Ireland. Everything indicates 

 that the now of water through the Irish Sea from South 

 to North runs transverse to this line, that is, between 

 Isle of Man and Anglesey. The drift-bottle experiments 

 themselves provide actual evidence; which is again sup- 

 ported by a study of the direction of the isohalines and 

 isotherms, since the flow of water obviously must 

 generally take place in a direction normal to these curves 

 at each point. It is also probable on a priori grounds 

 that the flow is in this direction since the prevalent 

 direction of strong winds is S.W. to N.W. ; while 

 Ferrel's Law shows that whatever tidal streams and 

 currents there are in the sea here must be deflected to 

 the East. It may be premised, therefore, that the water 

 between Anglesey and Calf of Man represents, in its 

 physical properties, the water further south in St. 

 George's Channel, and even outside the mouth of the 

 latter in the open Atlantic Ocean, and that variations of 

 temperature and salinity at Lancashire Hydrographic 

 Stations 5, 6 and 7 are probably parallel to those 

 occurring outside the Channel. 



