1G6 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



A careful consideration of the above tables will show 

 that: — 



(1) In the majority of cases the water at any given 

 spot has practically the same salinity from top to bottom. 

 There are, however, some well-marked exceptions to this, 

 the stations affected being in the shallower water north of 

 the 54 parallel of latitude. In these exceptional cases 

 there is a more or less rapid increase in salinity with 

 depth. The probable explanation of this will be 

 discussed presently. 



(2) There is a small but unmistakeable seasonal 

 variation in the salinities. 



To bring out this second point more clearly the 

 salinities at the chief stations for the various months have 

 been collected in the following table. In most cases the 

 salinities have been given to the first place of decimals, 

 and in the case of those stations in which the water at the 

 surface differed markedly in salinity from that at the 

 bottom both top and bottom salinities have been given. 



For the present purpose those positions which are 

 bracketed may be considered as one station. 



In so far as one is justified in drawing conclusions 

 from only a year and a-half's work, it would 

 appear that at the first four stations the salinity 

 is at a minimum somewhere about February. The 

 maximum salinity is not so well marked but seems to occur 

 between July and November. 



In the case of stations 5 and 6 exactly the reverse 

 holds, the maximum salinity occurring in February and 

 the minimum in November. Station 7 which, like 5 and 6, 

 is on the line Holyhead — Calf of Man, resembles stations 

 1-4 from the fact that the minimum salinity occurs about 

 February. 



This difference in the time of minimum salinity is 



