PHYSICAL INVESTIGATIONS. 165 



column 13. On the bottom the highest values are obtained in 

 mid-Channel and in Start Bay, decreasing slightly on the southern 

 coast, and more markedly to the east of the Bill of Portland. On 

 the surface, again, the highest values are found at stations Ila and 

 VIII, and on the southern side ; and the lowest off the English 

 coast, those to the east of the Bill of Portland being due to differ- 

 ences in the water, those to the west to differences of temperature. 



The results suggested by these observations may be summarised 

 as follows : 



(1) The waters of the Channel are subject to a peculiar circula- 

 tion, the nature of which cannot be determined without more ex- 

 tended investigation. 



(2) The distribution of temperature in Start Bay demands special 

 investigation. In this area we find the highest surface temperatures 

 and the lowest bottom temperatures, the warm surface layer being 

 about 6 fathoms in thickness, while at the same time there is no 

 change in the composition of the water. In Start Bay we have a 

 notedly good trawling-ground, and this confirms the result obtained 

 off the east coast of Scotland by Dr. Gribson as already quoted, and 

 again by myself,^ viz. that where we have true oceanic waters, un- 

 mixed with estuarine or river waters, subject to special temperature 

 conditions due to the presence of land or other causes, we find 

 favourable conditions for successful fishing. This result seems to be 

 to some extent borne out by observations on the Dogger Bank 

 fishing-grounds. 



What these temperature conditions actually are must be shown 

 by investigation. The preliminary trip in the Channel indicates 

 that more numerous and detailed temperature observations must be 

 made over a large area, and that the samples collected need not be 

 so numerous, but must in all cases be subjected to a rigorous exa- 

 mination of the greatest attainable accuracy. 



In conclusion, I may say that the material discussed in my paper 

 already quoted seems to me exceptionally valuable in the inquiry in 

 hand. Observations of surface temperature taken regularly on the 

 fishing -grounds by fishermen afford data of extreme interest even 

 when great accuracy is not attempted. I have tried to initiate such 

 observations amongst the local fishermen on these coasts, so far, 

 unfortunately, without much success. The Association will be glad 

 to supply instruments and books to any fisherman or seaman on any 

 part of the coast who will take such observations. 



During the winter months I hope also to investigate the conditions 

 of local estuarine waters in relation to fisheries. 



* Journ. Seott. Met. Soc.,' 1889, vol. viii, No. 6, p. 332. 



