496 KEPORT OF THE COUNCIL. 



Section IT.— HYDROGRAPHIC AND PLANKTON WORK 

 IN THE ENGLISH CHANNEL. 



In August, 1908, the southerly flow of comparatively fresh water 

 from the Irish Channel was well marked, and the salinity at Station 4, 

 near Parson's Bank, was much lower than in mid channel on the line 

 from Plymouth to Ushant. Any division into layers of varying 

 salinity was less than might have been expected during this month. 



By Novemljer salinities had increased everywhere in the English 

 Channel, and were nearly the same from surface to bottom. In the 

 Irish Channel, however, the Salter water normally found \inder the 

 north coast of Cornwall had spread some distance seawards, under the 

 influence of strong easterly winds, as a thin surface film. 



Hydrographic investigations had, at the end of 1908, been carried 

 out in the English Channel for six years, and had shown that the 

 water eastward of Start Point is nearly always of the same composi- 

 tion from surface to bottom. In view of the fact that surface water 

 samples are collected every fortnight on four cross-Channel steamers, it 

 was decided to confine the work eastwards of a line drawn from Start 

 Point to the Channel Islands to surface observations only, and to add 

 seven other stations to the westward of the area usually investigated. 

 Pive of these new stations lie on the eightli meridian, and No. 37, the 

 most southerly, is a short distance beyond the edge of the continental 

 plateau. The depths here vary very irregularly, but soundings of 

 from 400 to 500 fathoms are to be expected. 



The February cruise of 1909 was the first made under the new pro- 

 gramme. The water was everywhere nearly homosaline : at Station 

 37 the salinity was 35-53 °/„„ at all depths down to 450 m. (246 fthms.). 

 Unfortunately the wire was not long enough to allow of observations 

 below this depth, and no bottom was found. 



The observations in the Irish Channel in May, 1909, show rather 

 complicated conditions, a thick layer of salt water being here super- 

 imposed on one of lower salinity. It is probable that this distribution 

 is due, as in November, to strong easterly winds. 



At Station 37 the conditions were the same as in February, with the 

 exception that the temperatures were slightly lower, and the surface 

 layer had risen to 35-617.0 salinity. On the bottom, however, which was 

 not reached in February, the water had a salinity of 35-62 7oo and a 

 temperature of 13°. The high bottom salinity has been noticed by 

 several observers, and is generally attributed to a current from the 

 Mediterranean. Until further confirmation is forthcoming, however, 

 the high temperature must be considered doubtful, as it was measured 



