CLYDE SEA AREA. 711 



Here it is seen that the amount of sulphuric acid proportionally to chlorine in the 

 surface water increased steadily from November 1886 to June 1887, and fell off in a very 

 remarkable manner in September. With the exception of an increase in February 

 followed by a diminution in March, the same is true of the bottom water. February was 

 the month of minimum salinity in the whole Area, while in September the conditions 

 were very nearly the average. Taken in connection with the salinity curves, and the 

 data of the salinity trips, the sulphuric acid results are very puzzling. So far as can be 

 gathered from Mr Dickie's papers the method of analysis was the same in all cases, yet 

 the altogether exceptional lowness of nearly all the September results, and the fact that 

 almost all the very low values of the sulphuric acid ratios occur in that set of analyses 

 would seem to indicate that a different and probably less satisfactory method of analysis 

 had been employed. 



The alkalinity results are more uniform, and the maximum surface alkalinity 

 occurring in February is in accord with the very low surface salinity of that month, 

 but the very low bottom alkalinity (the minimum) associated with it is not easily 

 understood. 



Although too irregular in their variations to be of much value in elucidating the 

 changes consequent on the introduction of fresh water into the Sea Area, the chemical 

 results — if we omit those for September — show that the composition of sea water is on 

 the whole fairly constant, and that the proportion of sulphuric acid to chlorine is 

 distinctly higher than that of the open ocean. The ratio of sulphuric acid to total 

 halogen, estimated as chlorine, found by Professor Dittmar for the " Challenger" samples 

 from the open ocean, was 0"11576, that obtained by Dr Gibson for Moray Firth water 

 was - 11 707, while the amended mean of Mr Dickie's results for the Clyde Sea Area is 

 011755. 



It remains to discuss the chemical results for each station. 



[Table 



