SEA-FISHERIES LABORATORY. 175 



picked up off the Head of Kinsale, another in Anglesey, and 

 the third at the month of the River Boyne. 



This segregation may be accounted for by the action of 

 small local differences. Examples of these are eddies and 

 convection in the water, such as may be observed as far out 

 as twenty miles from Holyhead, due to the impinging of that 

 part of the tide which is following the coastal formation, upon 

 the central mass of water moving steadily up the centre of 

 channel ; water ripples which may be due to the presence 

 of banks and shallows, or even a catspaw of wind. These are 

 enough to disperse drift bottles in the earlier part of their 

 histories, and may determine into which general system the 

 bottle is finally going to be adopted. 



