SEA-FISHERIES LABORATORY. 143 



and sulphate, and also the chemical nature of the plankton, 

 but I hope to return to this work next summer, and take 

 up these matters. 



10. — Conclusion. 



On considering the results which I have so far deter- 

 mined it seems that the waters of the Irish Sea consist of 

 two types : — (i) that at the Isle of Man and in the deeper 

 parts around, and (??) that along the Lancashire coast. 



The former appears to be very little affected by tides, and 

 to have the salinity of ocean water, whilst the latter alters 

 very much both according to the tide and to the amount of 

 water poured out of the Mersey and other rivers. At low 

 tide the salinity as far out as the N.W. lightship is low, 

 whilst at high tide the water at the Liverpool Landing 

 Stage contains more salt than some other less estuarine 

 localities. 



The alkalinity seems very irregular. It is lower round 

 the coasts of the Isle of Man than in some of the more open 

 parts, as one might expect, but its height in some places in 

 Liverpool Bay is remarkable. Why in the Crosby Channel 

 almost at low tide it should be higher than at the Landing 

 Stage or the Isle of Man at high tide is not obvious ; or 

 again, why the highest value is obtained in the. Rock 

 Channel off New Brighton. 



No sections of the water of the Irish Sea can yet be given 

 as too few observations have been made, but the following 

 table * is a summary of all the results, and will give a fair 

 idea of the composition of the water in the different parts. 



* The .values now given supersede those in my table printed in the 

 L.M.B.G Annual Report. That table was incomplete and only approxi- 

 mate, as all the results had not then been worked out. 



