SEA-FISHERIES LABORATORY. 425 



OX THE DRIFT OF SEWAGE IN THE DOVEY 

 ESTUATIY IN RELATION TO THE MUSSEL BEDS. 



By Fred. W. Durlacher, 

 University College, Aberystwyth. 



(With Chart.) 



In all, I paid fonr visits to Aberdovey, each time 

 staying two days, except on the first occasion, when I 

 only stopped a few hours for a general look round. On 

 going down to the wharf on that day, two or three hours 

 after high tide, the presence of the sewage in the neigh- 

 bourhood was most evident; but I shall return to the 

 conditions at the sewer outfall later. 



I started actual observations with Captain Lewis the 

 following week, on Friday, 31st October, 1913. Each day 

 before commencing work with the floats we made a rapid 

 round in the launch of several stations I had fixed before- 

 hand as likely to be most interesting as regards salinities, 

 temperatures, &c, and we endeavoured to get readings at 

 those various spots, which I have marked on the map, 

 within as short a period as possible, while conditions were 

 fairly uniform. I have dealt with the hydrographical 

 readings separately. 



The floats we used were simply laths from a Venetian 

 blind, to which a small stick and flag were attached, 

 weighted at one end with a stone of sufficient size to keep 

 the whole thing upright. Such floats drew about 

 2 ft, 6 ins. of water, and were not likely to be much 

 affected by the wind. 



I will now deal in order with the results obtained 

 under the different sets of conditions. 



